There are 32 houses in Monopoly. That's only enough to cover eight properties with four houses each, or two full (three property) monopolies, plus one two property monopoly, either Boardwalk-Park Place, or Mediterranean-Baltic.
So if I own two full monopolies, and cover them with four houses each, there are only eight houses left, meaning that except for either Boardwalk-Park Place, or Mediterranean-Baltic, no third monopoly can go up to the crtical three house level on all three properties.
Does this mean that I should keep four houses each on my two monopolies and NOT upgrade them to hotels? Or if someone wants houses, maybe I should at least force them to give me another Monopoly (or railroads or cash) in order to agree to free up houses by upgrading to a hotel? (This might come into play if another opponent and I both had four houses each on our respective monopolies.)
(I remember playing years ago with two house rules: 1) if someone could cover all their properties with hotels outright they were allowed to do so without buying houses (if they could afford to do so), and 2) if someone had four houses on a property, you could force them to free up houses by paying for their upgrade to a hotel.)
What I find puzzling is that there are 12 hotels, enough to cover all the properties from four full (three-property) monopolies. And taken together, the hotels and houses can cover six full monopolies, plus a seventh, either Boardwalk-Park Place, or Mediterranean-Baltic, with either a hotel or four houses.
So was it the intent of the game designers that the board be covered this way? Or is a housing shortage just another "monopoly" that creates a further shortage over and above the physical building limits?