I went to pretty big lengths to keep breastfeeding, including having my dh and lo come to a conference in another country with me so I could keep breast feeding her at eight months. So to me, since you ask, it does sound selfish based on my own experience. But at the end of the day it's you making a choice about how you are raising your baby so it doesn't matter what we think or even what your baby thinks, you have all the control here. If formula feeding means you can have fun and freedom over the summer and that's the priority, go for it. As far as convenience is concerned, I have found breastfeeding really convenient in many ways, particularly when travelling, though it's a commitment, there's no denying that. Maybe instead of being all or none about it just leave a bottle of formula when you want the freedom to go out. It won't kill your baby to have formula for a night and breastfeeding is not as all consuming when they start having solids at six months.