I have a friend who had lasik eye surgery four years ago. He had an enhancement this year. Doctor told him that not all can have one surgery to solve all their vision problems. Some people do really need an enhancement after lasik eye surgery. So you can consult your doctor. I can't tell you how long lasik eye surgery can last, because to different people, situation changes. We can't get a definite munber.
Once I asked my optometrist that how long lasik eye surgery results will last. His answer is "it depends." He told me that if both eyes are corrected to 20/20 with a lasik eye surgery. The results depend on the stability of your prescription and age. Some people will suffer from vision problems until late 60's, at this time, cataract or some other eye condition occurs.