i have a rav4 2001 how often does the ac need servicing

You know the old saying, "if it ain't broke, don't fix it?" If it's 10 years old and blows colder air than your sisters 2 year old Renault, I would leave well enough alone. You should only have it serviced if the A/C light flashes or you notice that it starts blowing warmer air. That's usually an indication of it being low on gas.

I second Reelin68. dont touch it