Is swaddling mandatory?

I'm just curious if swaddling is a mandatory type thing people do now? All the women in my family say they never swaddled any of their children but when I look online people talk about swaddling being a must do thing. I have some of those "sleep sacks" the ones with no opening for the legs at the bottom and also some gerber sleepwear that have the mittens attached. Would that be good enough or should I buy a blanket to swaddle with just in case? Baby will be born in summer and unfortunately we don't have air condition or central air I don't know if that matters or not.