Right. In my case, the seasonality came from it being a pool - it was only worthwhile to pay nightwatchmen when it was actually filled and multi-million dollar liability existed for accidental drowning (read: middle-class teens holding drugged parties).

In a more 'real' nightwatch job, seasonality might not be a problem. On the other hand, you might have more supervision than I did. (Which was none. I saw my nominal boss once at the beginning.)

In any event, the free time was what you made of it. Akrasia was a major issue.