Scraping off old paint is a nightmare for all the DIYers out there who are mulling over repainting their house or anything else. Some people prefer to paint over old paint instead of removing the old paint. However, the problem with painting over the old paint is that the new layer of paint will flake off easily. Also, the old paint tends to poke out through the new layer. As the old saying goes, if you do it well, you only have to do it once. So, it is always recommended to scraper off the old paint thoroughly and make the surface smooth before putting on the new layer of paint.