My average lifespan for a phone is maybe 5 years.
Mine is around 4-5 too, if I can push it out that far. My last one was 4.5 and this one I hope will last a while too.
The expensive boots will save money in the long run.
In English there is a saying "to be well heeled"which means to have money.
Good boots are expensive to buy, but they can also be reheeled. Cheap shoes don't get fixed.