How many years does it take to get oral cancer from chewing tobacco?

Not sure: Cancer development generally requires a "latent' period to develop. How long that is, is different for different people and different cancers. Best to quit chewing tobacco, or to have never started.

Usually decades.: Most patients present at over 50 years of age, but alcohol and tobacco use (also smokeless) are risk factors and therefore some especially prone, heavy users may get it sooner. It would be best to stop all tobacco use as soon as you can.

Varies- Quit Tobacco: It usually takes years to decades, however, oral cancer has developed in teenagers using chewing tobacco. Quit the habit as it may take a short time in a suseptible individual. Other factors being hpv infection, immune status and genetic make-up of the person, .