How many sippy cups do I need?

[vikivoly]

I have 6 8-oz cups now. Do I need more? I feel like I'm often short handed because one will be in the car, the stroller, diaper bag, etc.. But I'm not sure whether to buy more or not. I read somewhere that she should be off of sippy cups by the time she's 18 months. Does that sound right? I don't really see her being responsible enough to handle a regular cup in 4 or 5 months.

[emmiem]

I think that is enough right now. My 3 year old still uses them but not full time. You end up throwing some away when you can't get the crevices clean anymore. You also lose some but I find I like to try different ones and don't want so many at one time.
emmie