At my company (US cargo operator) several things come into play. We're not paired together the whole month. I'll fly with 5 Captains this month. Some legs have three pilots, some four. First, some airports are Captain's landing only by company policy (Bagram, Quito, etc.) Second, if the weather requires a CAT II or III approach our policy is they are Captain's landings. (The other F/O on my last flight lost the landing because we had to do a CAT II approach.) Finally, if the plane is light and the c.g. aft, our policy is it's the Captain's TO. Since the reg on currency says three TOs and landings in the last 90 days, if they're going to get the TO, they may as well get the landing.
So when the crew meets up, one of the first things discussed is, "Who needs a landing?" Everyone walks around with their expiration date in mind. Captains do what they can to keep F/Os from pumpkining and having to go back to the sim for a currency checkride.