Is it ok to...?

get my transmission fluid changed at valvoline instant oil change. or will i have to go to a dealer? how often does this need done.Is it ok to...?
Depends on what kind of car. If your talking MB, BMW, etc. I would go to the dealer or someone who specializes in that type car.

I'm not a real fan of the " instant oil change" people. Normally your talking inexperienced teens doing the job.

They also usually use cheap (Fram) filters and not factory recommended filters.

Normally the X-mission filter and fluid change is about 30,000 miles unless you are towing or some other hard usageIs it ok to...?
It the car has in excess of 100,000 miles, take it to a dealer for that sells that make of car. When the fluid and filter are changed, he will inspect and adjust the bands if necessary. He'll also advise you of any metal particles found in the transmission pan.

Transmission oil changes at instant oil change businesses are OK after a hard towing job or overheating of the engine since the radiator cools both the engine water and the transmission oil.Is it ok to...?
i'd take it to a dealer or transmission shop.

I let the ten minute oil change guys top up my windsheild washer fluid and not much more.

changing transmission fluid and filter typically calls for removing the entire pan from the bottom transmission, and can leave you stranded in a hurry if done poorly.
In your hand book it will tell you how often to get it done. The dealership does not charge as more as peolpe think. For warranty reasons you should bring it to the dealership.....you never know what else might be going on and they will look for all that for FREE!