Given their age and how badly stored the often are I think opening them to make sure the case isn’t full of aphids or cookie crumbs before putting them in your player is probably the best habit. However I would refrain from ever touching the disc if possible. There are ways of cleaning them but if you don’t get them dirty you’ll never need to learn those tricks.
Like camera lenses or the human colon there are some things you should never touch even once if at all possible because there is no way to ever return them to factory original condition.
LDs can take an orbital sander, if it comes to that, totally different situation.