Wearable pump to standby

Ill be delivering in 3 months time, i have bought 1 medela harmony manual pump and bought 1 side of electric wearable breast pump (autumnz marvel). Do i need to buy another 1 side wearable breast pump or just stick to 1 first? As im not sure how my breastfeeding journey will be since this is my first time. #firsttimemom