Clothing on 3 month old

FTM here! Do you put a white onsie on underneath your baby’s outfit during the day? We do at night for our 3.5 month old. He sleeps with a onsie, footed pajamas and then a sleep sack. Is it necessary to put a onsie underneath during the day? My MIL started doing that and she put two pairs of socks on bc she thought he was cold. When I got home and picked him he was really toasty and I didn’t know he had two pairs of socks on until my husband told me later that night. We keep our house set to 70 both day and night.