Mmmm. My child voluntarily totally stopped breastfeeding at about 18 months old. She'd never used a bottle. The benefits of breast feeding aren't just in the milk istelf. The action of suckling is different to using a bottle; it helps the baby's mouth development. Breast fed babies fed on demand seem to have better appetite control too and suffer less from obsesity in the future.
There are also benefits to the mother too; it lowers the risks of certain cancers and it produces feel good hormones (tell me about that bit!) and you get massive boobs for nothing! It's also free and there's no risk of infection from unsterilised bottles and equipment. And it's easier to go out and about with having to warm up bottles, etc. The nappies of breast fed babies (before they start solids) smell quite pleasant too. You can also breast feed lying down semi-asleep at night, rather than having to warm up and hold a bottle.
Breast milk also changes to suit the weather, etc, so there's no nmeed to feed babies water when it's hot. Overall it's just much easier.
Apparently my grandmother (who had 13 children), breat fed them as toddlers. She always had babies and so it made sense to feed the slightly older ones too.
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