I'm not sure what you mean by AirMiles exactly by spelling it that way (is it a particular program's term for miles?), but with some airlines you get miles per stay and with other airlines you get miles per dollars spent, or if you choose points you get points per dollars spent.

A stay is defined as any consecutive nights at the same hotel, regardless of number of times you check out and check in. Thus you cannot get more stays on consecutive nights unless you stay at different hotels on alternate nights.

Regarding comments from other people who posted here:

It's more complicated as to whether to earn points or miles, depending on airline and PC elite level if any.

Find the airline earning terms for each airline at:

http://www.ichotelsgroup.com/h/d/pc/...s/airline.html

As you can see, generally US domestic airlines earn per dollars spent, and generally non-US airlines earn per stay. With those airlines which earn per stay, for one-night stays at inexpensive Expresses or Holiday Inns you're definitely better off taking miles direct. With those airlines which earn per dollars spent, it's a wash if there's no promo and you're not elite, but if you're either elite (or working towards it) or if using promos like the current "30000" one you're better of taking points and later converting.

And with American Airlines (and them only), you're always better off taking points if you'll save up a lot of them, because instead of the regular 4 points = 1 mile conversion with everyone else (and with AA at LOW conversion amounts), if you save up 67k points or more you can convert at a 2.7 points = 1 mile conversion rate. (While with AA and other airlines where you earn miles directly per dollars spent, you earn 4 times as many points per dollar spent as miles per dollar spent. That's why, without promo bonuses or elite bonuses, it can work out the same in many cases whether you collect miles directly or collect points and then convert.)

Meanwhile, some promos (like the current "30000") are per-night, while many others in the past have been per-stay.

So basically you can't assume anything simple and you have to look into each airline separately and each promo separately, since any time either changes it can tilt whether earning miles directly or earning points and later converting is better.