Bottle Debate

I first started contemplating taking the bottle from Annabelle a few months ago.  She is a pro at a sippy cup as well as a straw.  Her dad has said she could probably have used either of those since birth lol.  She only gets maybe 2 bottles a day since she is still a breastfed baby so I know that it will be very easy on us but for the baby sitter I'm not so sure.  She usually tells Jennifer when she wants a bah because it means she is ready for a nap.  Jennifer tried giving her milk once in a sippy and she wanted no part of that but now that she is a little bigger maybe she would be okay with it.  Even though we use very few bottles they are still a pain to clean.  I used to wash the bottle she used during the day as well as my breastfeeding bottles daily.  I have now started washing once a week.  I always hand wash these and it now takes up less time. 
Since we have been breast feeding for almost 15 months, the other question I get is when am I going to stop.  I'm not quite sure what people have against breastfeeing as Annabelle has never been sick, never had diarrhea, never had an ear infection, etc.  Maybe the breastfeeding doesnt have anything to do with it, maybe her immune system would have been just the same on formula, I don't know.  But I do know that I wouldn't have wanted to take that chance.  Even Jason asks when I'm going to stop, my answer to that is whenever Annabelle wants to stop.  In which he replies she will never stop.  We have never scheduled anything related to Annabelle, naps, feedings, etc.  At almost fifteen months old I'm definitely not going to start now.  I don't think that it is going to last much longer anyway, I do not like to use the word "weaning" but I do believe she will self wean in the near future.  Her nursing sessions only occur now when she is really tired or if she has been away from me for a long period of time.  She nurses every night but it is taking less and less nursing to get her to sleep.  I will be very content when she stops as it will be her time and she will be ready, which means that I am ready.  Of course I'm going to miss our time together but that time will be replaced with other time together just doing different things.   When the nursing stops then we will work on getting her in her bed, that is if her daddy cooperates :)