Nursing bra vs. nursing tank?

kirsten • Married for 4 years. Currently have a one year old princess💜 and a 1 week old prince💙
Are nursing tanks 100% necessary? I feel like just getting a couple good quality nursing bras will work. I am having a winter baby so If I got the tank i'd probably have another layer over it, but I would also have layers over the bra. Just needing some input!