I just read the manuals. A good few times.
Not really swayed by videos or other people’s opinions.
Only ever bought one device that I really wanted that turned out to sound like total, pure shite. Not telling though.
If it sparks imagination and ideas before you buy, it’s probably worth a bash.
EDIT (after 1like)
I must admit that Nord do have audio demos that have impressed me but not swayed me, more like reinforced my decision… NL4, NDs (not 3🤢)
Nice manuals too 
Always the music I’m currently into
Hip hop - samplers, pad controller
IDM - modular, elektrons
bands - guitars, basses, piano
I always want to make the music that I’m listening to, and the style influences my gear choice
2 things: fun and limitations
Gear must be fun for me to use. I like limitations, because I enjoy being able to “fill” something up. DT, for example, only 8 tracks to a pattern. When it’s done it’s done. I really enjoy gear that CAN be standalone, not that it has to be. Every piece I currently own has a sequencer lol (OP-1, OP-Z, DT, DN, Pocket operators).
I’ve got just the thread for you! 
Seriously though. I’ve found it difficult settling on the right setup. Change tends to be a constant for me in other areas of my life as well, but the initial decision to buy gear is usually made based upon extensive research via YouTube, forums (including joining user forums before having purchased and annoying the current users with noob questions - if I can’t already find the answers), the need to make a specific sound and finally the price.
E.g. I’d really like a DSI Evolver, but for what it is, I couldn’t currently justify the price tag. I’m saving up for an A4 Mk2 though, as it can fill the same hole creatively, and a lot more.
Ease of use and overall sound are more important than demos that are musically pleasant to me.
Because at the end of the day gear is not designed for specific genres, as long as you can input any notes you can play from Bach to country music in any of them.
Most of my gear has some strangely fascinating story to the point I feel it was destined to come to me…
I even made a thread about it, but forgot about it and still have many stories to add to it. It kinda rambles off on some tangents but anyway:
Also for me if a lot of people use some peice of gear I tend to use something else just to be different, but it’s not a strict rule…
Yep, I don’t buy anything to sound like someone else. There’s tons of great techno music done on Elektron machines, for example. I love techno, but don’t do a lot of that music myself.
Though I have steered clear of certain machines when I can’t find any sort of interesting music done on em, so there’s that 
I buy stuff to augment my weaknesses. I’m pretty comfortable getting what I want from synths so just use a few $15 ipad apps. I’m terrible at beat making and drum sounds so I bought a rytm.
There’s multiple electronic acts performing every week in my smallish mountain town in NorCal, many from bigger cities along the U.S. West Coast. I’ve never once seen an Elektron at a show and I’ve only spotted one A4 in someone’s studio. For me at least in my home turf Elektrons are rare and different. I’m the only one around here with an OT and I’ve only met one other person who knew what it was… I don’t make techno with them either… 
I realized early on that the process/workflow is most important to me.
Of course if it is a synth or something that you create sounds with, how it sounds matters to me as well.
& I prefer limited gear. For me having fun, gaining skill & gaining knowledge is more important than making a fire beat. I love this shit, it’s life, how you feel about my music isn’t important (all tho, when I put a lot of work into something & I get a good response from the public it IS a good feeling).
I want to know how to do as much as possible myself. If a machine does most of the work, I don’t feel proud of what “I” created. I LOVE a challenge. I like taking ugly sounds & making them beautiful. I like using gear that is considered for a specific genre & making a completely different genre with it.
It’s odd, I am NOT picky with gear, I’ll play with pretty much anything, yet I still do a TON of research prior to a purchase. There is just so much amazing gear out there & I haven’t been able to sell any of my gear, which now fills 3 rooms, so I’m being more & more careful with purchases since it’ll cause me anxiety to think of selling it.
I would say about half the gear I have, I researched for a year prior to buying (reading forums, reviews, watching youtube vids, asking questions, ect). & I ALWAYS read the manual prior to a purchase.
I’ve never met a single person that makes music, so I guess all my gear is different
Edit: Actually, about 15 - 20 years ago I visited a few studios, but they just used a computer. All the raves & clubs I’ve been to only used turntables or cd players… unless it was a concert with a live band.
I would love to go to a show where someone actually used hardware.
For me, the purchase decision is based on a coherent and streamlined workflow. GAS is triggered once i see that i can work self-contained with the machine if i want to - but that i can also integrate it into a setup im comfortable with. Im not a big fan of a desk full of machines with complicated MIDI Routings and weird Auto Paths until i reach the Main Out So i always take just one or two machines out of my cupboard, hook them up and make something with that. And only with that! Even if i could add other machines if i want to. I usually dont.
So … machines with multiple (Audio/Synth)-Tracks and a sophisticated Sequencer are a necessity for me! Thats why i own so much Elektron machines 
I can make something with just one single machine - but i can easily hook up more of them and keep track of what i do - thanks to the coherent and streamlined workflow they offer. This way i can keep it simple in the beginning and slowly expand the setup to a point there i have enough Tracks at my disposal without getting lost. Something that fits into this workflow and doesnt stand in its way is what i choose then i buy something new.
Generally I try to not buy anything at all. But over time GAS wins, that’s when I know I am making a sound (sic!) decision.
What’s driven a lot of gear choices since getting into Elektron a few years back:
I like the OP-1 for proudly being the strange little thing that it is. I like my Modor NF-1m as a general purpose poly because it’s “proudly digital” and has a strange character to its sound that I love. I love Monomachine because… man, there’s just nothing quite like that box. I love Digitone because my god it sounds great and finally seems set out to prove that FM doesn’t have to mean “DX7” clone, nor has to be a “fancy Yamaha workstation”.
Now I’m at the point where I feel that I’m almost “done” with my hardware collection. Famous last words, I know, but I’m at the point where I see some new synths come out and go “that’s nice” but realize it adds nothing to my setup. And I haven’t seen much of late that excites me.
my living situation has had the largest impact on the amount of gear in my possession
Small things my girlfriend won’t notice 
Ehem…
It has to meet certain functional criteria.
I am less intrigued by how it sounds. EQ/Comp/FX go a long way and can make weak sounds strong, and dull sounds bright/interesting. I’d rather deal with something dull/weak sounding that has the functionality mentioned above than something that sounds breathtaking but has no memory/sync/multi-outs/portability. I’ll take function over form every time.
Some factors I consider:
How supportive is the community? I look at whether there is good unofficial support for the instrument if it skews to the somewhat more complex side of things. I bought my OT because of the community. Before that I bought my MV-8000, thanks to the community. Don’t underestimate the power of community. You know you’re in the right place when other users are willing to downgrade their OS to a previous version so they can confirm a bug for another user.
Reliability and features at release 1.0. I know product life cycle management and I know that bug fixes are unavoidable. That said, I expect the unit to function as stated on the box and in the adverts. Period. This is non-negotiable.
On samplers, I/O flexibility is important to me. The 4 outs on the OT are what I consider bare minimum. I’d prefer 6-8 outputs like my other samplers, but then the OT isn’t a traditional sampler so I’m willing to deal with it.
On synths I look for character and flexibility. Complex instruments don’t scare me off as long as I get rewarded for my time and effort. I like to have a blend of analog, VA and digital synths as I feel I’m able to cover more ground than if I had a huge eurorack setup or 8 analog monosynths. I like variety and I appreciate an instrument for its strengths, I don’t get hung up on whatever perceived shortcomings might exist in the opinion of those on the internet. I expect the instrument to possess some novel characteristics.
I’m a sucker for hearing an incredible sound and deciding “I want that”.