I have a 15 month old daughter (who is amazing, but that's beside the point!) who is still having three breastfeeds a day. This isn't a problem but at some point these will inevitably decrease and I'm wondering what to replace them with? Cows milk, water, something else?
Sorry to be ignorant, but I could do with some help!
At 15 months you don't need to bother with formula unless you want to. Full fat (blue top) cows milk would be the easiest (and cheapest) swap to make.
Some people use follow on milks for 1yr+ but I personally think they are a waste of money. My 14 month old has cows milk in a lidded beaker at breakfast and then some before bath/bed/teethbrushing at night and just has water in the day time, though its only recently she has given up an afternoon drink of milk.
Probably depends on what time of day she bf's, if it's fairly regular. E.g. if she has a bf first thing in the morning, and then breakfast a bit later, you might find she's happy to just have water first thing and then a bigger breakfast. If she has a bf mid-morning you could swap it for a snack plus water. If she has an evening feed she's more likely to want to swap that for cow's milk than water. Although I don't think it's essential for older babies/toddlers to have cows milk as a drink specifically, if she has some with cereal and some yoghurt/cheese I would imagine she'll get enough of the calcium etc just from that. It sounds from your post that you are not currently intending to wean her from bf'ing at this point, so you may find that it evolves naturally into something else.
I first offered cowsmilk to DS as a drink at about 12 months (he went on to bf until 2yrs) and he didn't really drink any of it. By 18 months he was happily drinking it at bedtime and sometimes during the day. As Zimbah said tho, as long as they are getting calcium from other sources, milk as a drink is not so important.