I have same shit problem with w395 sony ericsson. therefore I don't want give the phone strip change or slider change. instead wasting money for rs 400 or there lies for 600rs.
I keep slider of sony ericsson always open. this will solve your problem. once you give for slider or strip change for last time.
keep always your slider open so that you can to slide the phone and damage your slider or strip.
however some times you may put in your pockets but don't worry. keep always you phone in open pockets not in tight jeans.
thank you, hope this solves your problem in future.