Gas tank leaks. How hard to replace? on 1991 Nissan Sentra

My gas tank leaks. How hard is it to replace?

Asked by for the 1991 Nissan Sentra
My labor guide shows it is about a 2 to 2.5 hour labor operation to replace but I think it is not that difficult. It is under the car requires the fuel tank to be drained the vehicle properly supported (safely), fuel is flammable so risk associated there, but it not a job out of the scope of someone mechanically inclined once proper safety precautions are followed.