"The Laptop Rule" vs What?

A young man I know has passed on to me what some in his generation regard as a humorous epigram called "the laptop rule." This is supposedly a rule by which a male is supposed to choose girlfriends. I searched high and low for the opposite equivalent: a pithy, crassly facetious expression of how a young woman might select a boyfriend. I confess that I have failed.

Here's where the sexes fail totally to even connect! OK, by this point you're probably wondering what the laptop rule states. Here it is in its full glory:

Every three years get one that is thinner, faster and does more things.

That's more or less an apt description of the march of laptop technology. Of course, that's because laptops are built with obsolescence in mind. 

Personally, I hate laptops. I bought a desktop PC in 1991 that I managed to keep in operation until about 2001 -- by which time only the actual box and the floppy drive was original.

Similarly, my most significant relationships have tended never to end. I retain some contact with friends from infancy, second grade, high school and university, even though they are spread out through three continents.

The laptop rule might be a way to describe retrospectively a sowing-wild-oats period, but as a rule of thumb for life, it thumbsucks, if you will.

Never mind that. "Don't women have a similarly pithy rule?" I asked of several female friends. Like what, they wanted to know. 

Oh, say, like the Loco Rule: never get close to a locomotive unless it hitches up. Too 20th (or 19th?) century.

Or how about the ATM Rule: get a new one when money stops being dispensed. That's a guy talking.

Or ... I give up. Anyone know one?