Based on the other responses to this, I’d say it really varies from person to person.

In my case, Kdenlive does in fact tend to crash often the longer I use it in a single session. It tends to get unstable on my system after around 2-3 hours of continuous work.

I remember losing an hour’s worth of progress once, and from that point I’ve been saving my stuff compulsively. At least it taught me good habits!