I started using reusable breastpads with my 3rd child and wish I had known about there with my first. I dread to think how many disposable breastpads I used as I breastfeed my 1st 2 kids for 10 and 16 months and needed to wear breastpads until I weaned them. Resuable breast pads are a great investment as you just need 4-6 pairs, rotate using and washing them and then you never need to buy them again. You definitely come out ahead financially using wool breastpads, plus they are better for you and the environment.
Reusable, just wash and ready to use again
Very absorbent
Large size that shapes to the breast and isn't visible under clothing
Can leak and show wet spots
Don't cope with a fast let down very well