I looked into leather repair a while back, after one out of town pro shop guy mentioned that he did such repairs on skates. Basically, he stripped off the old clear coat and probably the old polish, buffed the leather, and applied a leather prep, new polish, and maybe a new clear coat layer. There are also leather repair fluids that can fill large gashes.
A fair number of people have just applied new polish - probably not as durable, but fast.
But I never got around to doing it myself.
You might affect the breathability of your skates, which might matter if you have warm sweaty feet.
I often use the thin nylon boot covers that many pro shops sell. It reduces wear and makes it easier to do lunges, but they sometimes need to be replaced. Some of the kids around here have done elaborate paint jobs on their covers, and some of the girls use over-the-boot tights instead. (I wonder how often tights need replacement.)
I never tried the thick warm neoprene covers - perhaps they don't need replacement.
I'll leave talking about tape to those who use it.