Should you plug your device in more frequently and wear out the MicroUSB port, or let the Li-Ion battery drain more and wear out the cells?
I think the simple answer here is what is cheaper. Connectors are reliable, yes, but they're also extremely cheap when we are talking about USB. I'd rather replace it twenty times over than replace the battery if I need to at all. That said, finding replacement batteries can also be a hassle, so I'm going with plug away.