I leave mine in until it needs a new replacement. Dunno how long the present bit has been in there (the one I normally use for what I do), but it's been over a year I am sure. No problems. If I need a different style bit I just put in a different router, with the bit I want.
"It ain't what you're told, it's what you know." - Granny Weatherwax
Fawkahwe tribal police SWAT Team
Some days, the supply of available curse words is insufficient to meet my demands.
.....Call me a craftsman, artisan, or artistic, and I will accept that. Call me an artist and you will likely get a quite rude comment in return. I am not a @#$%ing artist.