Spark plugs : when should I change them and what type of auto mechanic can I take them too

I’m hitting 70000 miles soon. in my Toyota corolla 2021. I do maintenance on it but when coming to spark plugs imma leave it to a professional. which type of mechanic can I take it too, and also I’m not trying to pay and arm or with my arse at the dealership. and should I get a tune up i never got one done either .