If you get a reputable brand, it'll last a very long time.

I'd go mostly off how you intend to use it, and what firearm(s) it will be mounted on. I wanted two things in mine, durability and versatility. At work, I'd used Surefire suppressors, and was familiar with them, but I also looked at offerings from Gemtech, OSS, Silencerco, etc. I already had several Surefire muzzle devices, really liked their QD style and system, and had seen several Surefire SWAT cans that had taken a real beating and were still working flawlessly.

Ultimately, I went with a Surefire SOCOM 300 SPS, and it works perfectly for what I need. It's a lightning fast swap between all my rifles that have Surefire fast attach muzzle brakes and flash hiders, and suppresses everything from my .308 M40 rifle to my 300 BLK and 5.56 SBR's. I use mine on 5 different rigs.

Some people value versatility, some need FA capability/rating, some want the ultimate quiet/low sound for a particular caliber or firearm setup, others prioritize looks and cosmetics - I'd look for which suppressor fits your intended purpose the best.

Lots of good ones out there, but I love my Surefire SOCOM. I looked into getting a handgun suppressor, and top of my list for that was the Silencerco Octane, with a piston for .45 and one for 9mm. By the time I added the cost of the can, stamp, pistons, threaded barrels for my handguns, it ended up being more than I wanted to spend - but that's the model that would have worked best for me on the handgun platform.