How often for professional cleaning?

I recently purchased a Canon t3i to start making short films and take pictures with. I plan on using it quite a bit, since I don't trust myself to clean it how often should I take it to the camera store to get it professionally cleaned and tuned up?

I was thinking every 6 months to a year.

Also about how much does a cleaning cost?

I sent my old Nikon D300 in for a tune up and cleaning after about 6 years of use. I only sent it in because after being hammered by a football player on the sidelines, the auto-focus was becoming intermittent.

While it was visiting Nikon Services, they replaced auto focus system, bottom plate, cleaned the sensor and replaced the shutter… All for under $250. It came back looking like new.

Unless you have specific issues you can attribute to dust and other things inside the camera, don't worry about it.

I own a t3i and it's an excellent camera however it doesn't do film… It does video. In fact no digital camera does film. If it's film you want you'll have to look at film cameras.

Cleaning? Well that depends on the previous owner. How did he/she treat the camera, where was it used and all those kinds of questions. If you don't trust it get the work done.

I wouldn't have it cleaned as often as that. Probably once every three years would be right, if you are going to use it above average.
For normal use, I would think about every five years.