Just don't think about it. Kagi keeps track of it and they do not charge for anything extra. They will tell you when you reached your limit. At first I also thought I would have to think about and not search for anything unnecessary to keep the usage low, but now I just blast away without thinking about it and I have so far never reached the monthly limit of 300 for the $5 plan.
It's refreshing to not have any ads and know there is no hidden agenda behind the search results.
