What is the life expectancy of one of these builder grade tubs. It is in very good condition now with plenty of gloss to the paint. Original to the house built in 93, I am carefull to not clean it with any harsh chemicals that will scratch. I am going to change out the tile in this bathroom and it would be a real time and money saver not to swap out the tub however, I would not want to find out after the fact that the tub is a gonner after all the tile went up.