Gaiters are ok,but I never really cared for the look.
When I was growing up most people would take them off as they liked the look better.
They are fine as long as you inspect them and the fork tubes regularly(especially if you power wash it),keep the bike out of the weather/garaged.
If the bike is a on/off road Scrambler style where you are riding with others on gravel/sandy roads then I could see the benefit of using them.
In the long run they could cause more harm than good if you don't inspect and maintain your bike regularly.
My CB200T had a set on them when I picked it up,they were ripped and I of course feared the worse.
The bike sat outside for a long,long time both at the guy's house I got it from and the salvage yard he got it from.
Well,I got the bike home and the first thing I checked was the fork tubes and you guessed it RUST and lots of it, all the way to the raw steel under the chrome. The fork tubes are pretty much unusable and would cost more to repair than to replace.
All the water,dust/dirt,leaves,bugs etc. got trapped in the torn gaiters and had nowhere to go. If the bike didn't have gaiters they wouldn't have ripped(DUH) and my forks may have,just may have been salvageable. I have seen this time and time again with bikes sitting in salvage yards.
When I see a old bike with gaiters I go over and more times than not there is more damage CAUSED by using them then they ever prevented.
I have 7-8 other bikes waiting to be dismantled that sat out just as long or longer than the CB did and the forks on most of them are usable.
Just my thoughts on the matter,but personally on a street bike I won't use them.