Breastfeeding after one year?

How many moms out there continued to breastfeed after a year? My twins were born almost a year ago. I never intended to breastfeed for so long but for for a couple of reasons I'm thinking I would like to continue. I've had problems with traditional breastfeeding and have been doing mostly bottle feeding. But as my twins get bigger, I think I will be more successful with regular breastfeeding. I would eventually like that bond. So I'm thinking of continuing. Any pros or cons to this?