I'm really happy with my sponges; have been using the same ones for over a year and they are still in good nick. I only use a carbon sponge for special occasions though; have replaced it with another ordinary sponge.
What I do is I rinse one sponge at a time; so in my bigger tank I have 4 sponges, that means one gets rinsed (=very gently swished in old tank water) about once a week, or a little less frequently. So I'm never cleaning out the whole lot at one time.
As for the filter floss, I used to change it every week. Now I've got more stingy, so I see if I can rinse it out first and make it do for another week.