Rubbish,if it was fast enough three years ago,then it will still be fast enough today,unless you realy NEED the slight increase then just reset the phone,it will be as fast as when new..
Only works for folk who don't need the latest,pricey shiney toy,which will only be slightly faster than last year's,smartphones are very nearly at the point that pc's have,tiny incremental speed increases,at the price of lots of money..