I plan to EBF for the first 4-6 weeks, then introduce a bottle so LO has time to "get used to" taking a bottle every now and then for when I go back to work and he goes to daycare (and for when I need to be away from LO for longer than 2-3 hours). Do I need to buy a breast pump now for any reason, or can it wait until we are ready to introduce a bottle?