I wear "house clothes" which are just basically lounge pants and whatever shirt I'm wearing for the day around the house, when I go out I throw on jeans. When I come back home I put my comfy pants back on first thing when I walk in the door. My husband has remarked many times how fast I can get out of my jeans once I walk in the door...LOL If I wear a fancy shirt I change that when I get home as well and put on just a regular t-shirt. So, I don't have PJ's per-se. I just sleep in the lounge pants and my t-shirt.
I don't think the kids have to have actual pajamas, you just have to have something clean and comfortable for them to sleep in. My kids get dressed and wear jeans everyday so sleeping in them would be really uncomfortable. But in some situations you could get away with not having any PJ's at all like the previous poster who said her DC only wears lounge type clothing because of the sensory issues. My kids have a mix of sweats, fleece pants and t-shirts that are too crummy to wear out but still good enough to sleep in. The actual pajamas that the kids have were given to them as gifts or hand-me-downs. My youngest does have more actual pj's because he still wears footie pj's to sleep in at night. I've been trying to get away from buying actual pajamas because of the flame retardants, so I'd rather them wear lounge clothes to bed instead, which could be worn during the day as well. But I do like to keep the clothes they wear for bed separate than the clothes they wear out.