don’t ever try to startle or terrify while using the litter box. the litter box is a kind of thing that is bought once throughout the time. so try to buy something with quality even if you have to spend some extra money over it. and there is also a thing that cats don’t like changes, so once bought litter box can be used for longer times. don’t use any kind of odor spray or something like this that irritate or might deter the cat from the litter box.
you need to keep in mind that the needs of a kitten and adult cat are different. they are different in size 