I'm not like a sponge connoisseur, but I've been using "O-Cedar Scrunge" sponges for about a year and they're pretty rugged. I have two sponges in rotation, and every time I do a dishwasher load I alternate them through it. They've never really fallen apart on me, but I think the green scratchy side gets a little less scratchy over time, and I just replace both of them every 2-3 months for good measure. I'm assuming that there's a scientific paper somewhere that says using sponges for that long will kill me or something, but I'm still alive so far so fingers crossed.