I used to do a lot of long stays at various all-suites brands: never ran into the "leave for a day" thing. Settling up monthly was always a thing - plus the hotel would happily settle you up at any time if you wanted to close out a stay for the purposes of elite tier leveling up.

Like Hipplewm it was always OPM so I never delved into the world of tax refunds. We always had a generous corp rate on long stays so price-wise I had no complaints. At the time, I assumed more than anything, the hotel just wanted to keep their books relatively current. Didn't matter to me - I would run an expense report as soon as I had a new receipt in hand.

This was mostly early 2000's - there was also no limitation on being checked into two hotels in the same brand on the same night. For example, I'd be at a Residence Inn in Dallas for 3 months....but also have a weekend stay at a Marriott in New York, and everything posted fine. In more recent years, I've heard this can cause problems and even get a guest accused of some type of fraud. (Reselling rooms for profit, in theory, I guess...)