Actually, more so - once you get the license (actually, the proper term is “certificate”) you have it for life. However, there are some things you have to do in order to keep “current”. In other words, once licensed you’re licensed for life, but there are requirements beyond a license alone in order to fly legally.
Yes.
How often you need these is determined by age, what you’re planning to do, and sometimes health conditions.
For a private pilot you need a 3rd class medical. If you’re under 40 you need one every three years, over 40 every 2. At some point in advanced old age they might require this even more frequently, but there’s no hard and fast rule, nor is there an upper age limit. I believe the oldest licensed pilot still flying was 102 (he passed away at 103). There is a woman in Tenneessee still working as a FAA designated examiner at the age of… um… she’s either 94 or 95.
A second class medical is needed for most types of commercial flying. Those are good for one year, after which they essentially become 3rd class.
Airline pilots - the folks who carry passengers - require a 1st class medical, which is good for only six months. It’s fairly intense from what I hear, and includes things like heart stress test (actually, not having had one, I’m not 100% sure of these things).
Certain medical conditions - like type II diabetes - will make getting a physical very difficult. Type I - insulin dependent - diabetes used to ground you for life, but the FAA is starting to allow a few to fly with a 3rd class, and I think there is a single one with a 2nd Class. Heart disease used to ground a person for life, too, but again, they are allowing people to go back to flying after heart surgery IF they meet certain stringent criteria, and such people may have to go back more frequently than they would otherwise. If you had such a condition, you have to prove it’s absolutely under control.
Other conditions - like a missing limb or eye - require what’s known as a “medical checkride” which you only have to take once. The purpose is to demonstrate that even though you have this problem you still have full control of the airplane and are not a hazard to others. So there are companies that make hand controls for rudder pedals for people who are in wheelchairs. There’s at least one airshow stunt pilot who is a double arm amputee. Anyhow, after you take a medical checkride you get a “SODA” which is a “statement of demonstrated ability”. I carry one myself because I am colorblind.
So, in order to use that license you need a valid and current medical, and that’s what gets renewed periodically. And if you have a SODA you may need to carry that with you, too.
A minimum of every two years you need to have a biennial flight review or the equivalent (checkride, Wings program). It’s basically a brief review of your flying skills by a qualified instructor, and some “ground school” to basically make sure you’re current on the regulations.
There are also requirements about a minimum hours in a time period for other things. For instance, no carrying passengers at night unless you’ve had at least three take-offs and landings after dark in the previous 90 days.
The truth is, 99% of the pilots do far more than just the minimum. Which is a good thing. But also, we got the license to fly, right? Not just hang it on the wall.
If you don’t fulfill the hour requirements you don’t lose your license. You do lose the authority to use it, though, until you are “current” again. So if, hypothetically, a pilot stopped flying for 10 years (reason doesn’t matter) then, before he could legally fly again, he’d have to pass a medical and have a bienniel flight review.
Now, there are some types of flying that do require a license but not a medical. Glider pilots and balloonists “self-certify” that they are fit to fly, basically they say that they have no known medical condition that could lead to sudden incapacitation. How, exactly, that works I don’t know, I don’t fly those things (yet). I believe these folks still have a bienniel flight review requirement.
And ultralights require neither medical nor license in the United States. To be honest, training is not required either. This is justified in part because they are only permitted to have one seat so only the pilot is at risk. Apparently the FAA doesn’t mind much if you kill yourself, but they do get cranky if you kill or hurt other people.