The best way to stop your guttering and downpipes rusting out and prematurely aging is to keep them clean and unblocked.
Blocked gutters can also cause overflow over the back of the gutter and down the barge board or up under your roof causing damp problems in your house.
It is a painful but necessary part of home maintenance but will save you money down the track. Maybe consider some gutter guard mesh to stop it happening in future.