When I first began doing diaper research (lo, these many years ago!) I came across lots of people claiming that their diapers were lasting through "all their kids," and other claims of nearly immortal longevity. This, even with pocket diapers, which people claim are less durable than prefolds. Lots of people added caveats to that statement - it depends on your routine, it depends on how many diapers are in your stash, the kind of diaper, your definition of "worn out," so on and so forth. But all that stuck in my brain was people saying that I should be able to diaper 2 or 3 kids with my initial stash of BumGenius 2.0 diapers. I even told my husband (in an effort to mentally justify paying $17+ dollars per diaper) that once we bought this set of diapers, we shouldn't have to buy diapers for a long time!
I was wrong.
Now, as I read through sites, I'm finding more and more references to expecting to get 150-200 wears/washes out of any given diaper. This makes a lot more sense than claims of lasting "forever."
My personal experience with the diapers certainly back this up. I've beaten up so many diapers in the past few years.
A bit of my dead-diaper history:
I had a batch of bumgenius 2.0 pocket diapers that died (elastic failed) after about 8 months of use. They were replaced at no cost to me, since they were under warranty.
I had a batch of cotton prefolds that also died an untimely death after about 6 months of use, for no clear reason, but there might have been a bleaching accident of some sort. I never did figure it out.
My replaced set of bumgenius diapers (a mix of 2.0 and 3.0) lasted for about 2 more years. Before 2 years was up, I was lamenting the bad elastic, aplix, and some leaks coming through the cover on the green 3.0 diapers (this was failed PUL, but I didn't mess with trying to get them replaced, since I felt I'd gotten fair use). I used these less and less until I finally gave in and bought a new batch (oh, the joy!) of bumgenius 3.0 and fuzzibunz one size diapers. The appear to be going strong at a year of use (2 kids simultaneously in the same set of diapers). Lest you think these are miracle diapers - I liberally use prefolds and covers during the week, so the pocket diapers aren't in constant use.
The replacement batch of prefolds that I mentioned above are starting to die. I used these diapers on E from about a year old (I'm guessing) until 3 years old. I bought some new (better sized, organic) prefolds for N, and they are still in great condition.
On the upside of lasting - I have a couple of bummis covers that I still use after 3 years. The elastic is a little stretched, the velcro is curling, and the leg seams wick if I leave a diaper on too long, but they work well enough that I keep them for use at home. I don't think I've had a problem of leaking onto clothing since N started wearing them.
I also have newborn/small diapers that have been used on 3 kids - I loaned them to a relative between my 2 babies. That might sound impressive, but really, they've been used for about 10 months total. Babies don't stay in the little sizes very long!
If cloth doesn't last, how can I save money?
Remember my post from a few years ago, evaluating the cost of diapering (as featured over at The Simple Dollar)? It still applies - it was still cheaper for me to go with cloth, because I certainly got lots of use out of them.
I've calculated that for a BumGenius onesize pocket diaper to pay for itself, I'd have to get about 112 uses out of it. So, if a diaper lasts 150+ washes, then one diapers pays for itself and then some (based $17.95 per bum genius diaper/ $.16 per premium brand diaper)
If you do some other calculating -
If all you had were 12 onesize diapers, and you only changed diapers 6 times a day, then over the course of a week, one diaper would be washed 3-4 times. Even if it was washed 4 times in a week, after 150 washes, you would be at about 38 weeks. At 200 washes, you'd be at 50 weeks - nearly one year.
With just 12 diapers, washing every other day, you could reasonably expect to get a solid year of use before they be at the end of it's life span. That is certainly not "lasting forever."
However, most people I know who cloth diaper full-time have a much larger stash than 12 diapers. I certainly do! My stash is large enough that any given diaper is washed about once a week (with one kid in diapers). At that rate, it is certainly reasonable to expect the diapers to last through 2 years.
So what can I conclude from all of this?
Don't expect diapers to last forever. Don't expect them to last a certain number of kids, or years. It's much more reasonable to expect a certain number of wears/washes out of a diaper. I think 150-200 washes is reasonable.
Here are some places that mention this very issue: