I've noticed my lint filter doesn't have much in it. Should I be worried it's building up somewhere?..

Robin, there’s a good chance that lint is getting trapped somewhere else if it’s not in the lint screen. We do advise replacing it if it’s a bit bent, warped, or just not working properly. I’ll add a link below for it. But until then, it’d be best o clean out the dryer cabinet, by taking off the panels and vacuuming out any build up you can see. We’d also suggest cleaning out your dryer vent, or having the entire thing (to the outside vent) professionally cleared. People often forget about this and it’s very necessary to prevent build ,p and in more serious cases, fires.