I'm not sure that's true in practice. Chargers are often shared in a household and you may not have control over people putting things back on the charger. My preference is to have something that charges more quickly, rather than a bunch of spare batteries.
Plus if you leave batteries on the overcharge-style charger for long periods of time, I'm pretty sure they just dissipate the extra charge as heat, and that charge is applied indefinitely. They essentially turn into little electric space heaters, sending that energy down the drain.
Don't leave them in the charger! You precharge and then store for a year+. Modern NiMHs only need topping off once per year or less.
So you have two piles. Good charged NiMHs and uncharged depleted NiMHs. While(uncharged.size() >= 2) put them in charger.
Then once per year, do a refresh charge on all the NiMHs. Easy-peasy.