One timeout is lost at the half of the four. The other three carry over and one is added in the second half. Hence coaches tend to burn one if they haven't already near the end of the first half just to practice timeout adjustments and hopefully end the half ahead.
You know the game isn't going well if you start the second half with three. Or don't have any by the fifth minute of the second half. If Buzz has extras he often does one at 5, 2, and 1 in the second half to just get the team refocused. If that isn't needed one might last until the 30 second mark. If it's going very well he doesn't use them all.
That we closed to a couple of scores several times means we were in the game in spite of the fans instinct to give up. Some of those we pulled out and won. I certainly prefer wire to wire leads. But against good teams you expect back avd gotyj because basketball is momentum oriented and streaky. I think most coaches seem to use timeouts to break "streaks" but my coaches were seeing things they wanted to address and it also gave us a breather and a mental reset.