Since it’s the summer and temperatures are hot in the south, I’ll sleep in either 19 or 20. During the winter, I’ll wear 3 or 4 (Boys boxers are comfy to me lol). As a mom, If I’m wearing 19 or 20 I’ll usually keep a cotton tee on standby in case my preteen son knocks on my door in the middle of the night.
Consistent through the year, sparing on both pyjamas and laundry, 17 to 20 are the way to go