In 2012, some people claimed all the cards and wrote all the things. Dwimordene said, that year: Fandom knows no sleep, fandom needs no sleep. (Or something like that.) Others ended up with a backlog of WIPs they were still catching up on in 2016 (there was a B2MeM round that year that was especially designed for catching up).

So the ten-card rule is partly to save us from ourselves!

I suppose: take a step back and ask yourself what you might realistically want to write in March, whether it's a long-running project or an entirely new one. Then select cards mainly to go with that, and maybe something extra, for spice.

And if, in March, divine inspiration/madness strikes? You can still write it and post it. After all, what does divine inspiration care about achieving a bingo, anyway?