If 999 out of a thousand valves are in spec, that in no way means your valves are in spec. You want to gamble and not do the recommended maintenance, go right ahead, knock yourself out.
But you dont know what you dont know, and you can't know unless you check.
Realize that valve adjustment also affects valve timing, which affects engine vacuum. I find it interesting that owners will spend all kinds of $$$ on farkles, and items they think are upgrades like exhausts and power commanders, but wont do the basic maintenance which can have yield the most improvement. I have many, but one particular horror story concerned a rider in my club with an '08 CBR900rr that had a poor idle and a rough feel. He spend $$$$$ on all kinds of stuff over a 2 year period. I had him bring it over, measured exhaust header temperatures, ran a compression test, followed by a leakdown test and... The problem the whole time was intake valves way too tight.
Get the service info, get some tools, and if you think you are able, at least check your valve clearance. It's not rocket science or brain surgery.
For a feeler gauge set, this is what I use and recommend. They are perfect for those valves where a conventional feeler gause set is too wide--like, for example, Yamaha 5-valve heads. Inexpensive as well.