I have always used Samsung phones, both for web browsing and phone calls. I normally buy them a couple of years after a new model has been introduced. I find that frequent "cleaning" with CCleaner keeps them quicker than not doing so. I try to keep everything off them that would be better done on a pc. I clear browsing data at least once a day. I do not have your issue with Skydemon, so when I pass my old one on to SWMBO, it gets wiped completely.