long chains will get loose sooner, hard shifting will knock it around and shorten its life, infrequent oil changes will interfere with lubrication as the carbon biulds up on the chain. most engines either have a auto tensioner, or a good guide to help it from slaping ,belts are good but some are very hard to change, to bad the manufactuers dont try to make the belt easy to change as it isneeds to be replaced at some significant exspence

Long chains will get loose sooner, hard shifting will knock it around and shorten its life, infrequent oil changes will interfere with lubrication as the carbon builds up on the chain. Most engines either have an automatic tensioner, or a good guide to help it from slapping. Belts are good, but some are very hard to change. Too bad manufacturers don't try to make the belt easier to change as it is needed to be replaced at some significant expense.