I often do meditation without a timer too. But I find it a good practice to try and do a certain amount of time, instead of however much you feel like. As that quickly turns into stopping meditation early to chase some interesting thought/idea.

Also, when meditating in the morning, it's good to know when you need to stop and start getting ready to go out. Otherwise I would be late very often.

Kitchen timer would probably scare the hell out of my partner. We have a very noisy one!