If you know what you are doing it is far cheaper to rebuild an engine than to get a replacement. To do a decent job all of the rings and bearings will need to be replaced, the bores would have to be honed and all the gaskets and seals will need to be replaced- this includes all valve stem seals, reseating the valves etc.
If you have limited mechanical knowledge it would not be advisable if it is your daily driver.
I have rebuilt that many engines that it is possible to pull em in the morning, rebuild in the afternoon and have 'em back in and running that night.
Yes,it would. Worn rings and valve guides/seals cause oil burning. These and other components are replaced with rebuild, basically bringing engine to like-new specs.
But you need to price it, as it could be more expensive than buying an other car, and what condition the rest of the car is, so yiu spend your money wisely.
Yes, when an engine ages the rings become worn and it can leak compression and oil. Another thing is that when the seals go bad it could be pulling oil up out of the crankcase into the intake. There is also a valve that is on the intake which connects the crankcase to the intake. This valve can go bad and allow oil to get into the intake and it will burn oil. I don't know what the engine is so I can only list the main general causes.
I always thought the sign of burning oil was because the engine was aging, and seals are beginning to leak the oil into the cylinders, so rebuilding an engine and replacing the gaskets should solve it right? Or is this issue not possible?