I've also heard of a 10 year limit, but it's not set in stone. Depends on the school. Basically, if you've got pre-req classes that are very old, if you can, have some updated science classes (helps to have letters of rec from more recent profs as well) and do even better on MCAT. If you do well on the test, which is only valid for 3 years, it will show that you still know the material and shouldn't be a problem. I've got real old chem and bio courses and have had no issue at LECOM or TUCOM. But it might be best to double check with your 1st and 2nd choice schools at least- better to be sure.