One of the users on Photo.net is a chemical engineer who worked at Kodak for ~30 years. He posted the following information in a thread over there about Life expectancy for refrigerated film:

In all cases where we are using film past its expiration date, the only safe approach is to try a roll OF EACH PRODUCT and evaluate it before shooting the rest of that product. The stability of film products is different for different products.

Having said that, here are some general guidelines. The expiration date for many products is about 2 years after manufacture. Refrigeration will preserve the the chemical properties of film for 2 to 4 times longer than at room temperature. If you bought fresh film and refrigerated it, the chemical properties should last 4 to 8 years instead of 2.

Freezing will preserve the chemical properties for something like 8 to 16 times longer than at room temperature. Frozen film can be expected to maintain chemical properties for 16 to 32 years.

Unless you have access to a salt mine, background radiation cannot be stopped by any process that any of us can afford. Background radiation causes fog and grain increases in the shadow areas. All films are sensitive to background radiation ROUGHLY in proportion to film speed. That is, an 800 speed film would be roughly 32 times as sensitive as a 25 speed film. This is very rough since the current Kodak 800 speed film is about 1/4 as sensitive as the generation from 8 years ago. All these discussions of keeping film in a refrigerator or freezer should only apply to low speed films (200 or slower). With high speed films, the background radiation will degrade the film regardless of the storage temperature.

FWIW, I've shot K-64 that had been in my freezer for 20 years with good results. I don't shoot 800 speed film that has only 6 months until expiration.

In fact there is a ton of information about this on Photo.net if you search around.

There are also some questions here that could be useful:

• Does film (get a chance to) degrade before sale?
• How do I prepare frozen/refrigerated film for use?

Kodak and Fujifilm are still making high-quality, fresh, reliable, gorgeous colour film. Take a look at (for example) Freestyle Photographic Supplies to see other current manufacturers. I would encourage any budding film user to buy fresh film - you don't need to worry about storage conditions, and you are supporting continued film manufacture.