I agree too. Once a week.
The reason I do that is if a colony moves in the day after I check, that gives them only a week of building in the swarm box, before I return for another check. That is short enough to remove them before they build too much in the swarm box and make a mess of things.
If they have just moved in, then I transfer them to a hive immediately.
If they are building but have no brood, then I know to come back in a few days when they have brood.
If they have already set up brood, then I move them to a permanent hive.
I recently helpd a guy with a swarm trap that had been occupied for 4 weeks. It was a two man job moving the colony into a hive box. Every single frame was filled with comb, but then had more comb hanging from the bottom of it. Fortunately, it was mostly cutting out and rubber banding brood comb into additional frames, and even that was mostly straight built. If it had been cross comb, or if there had been a lot of nectar, it would have been a royal mess.