I love my HRM. I workout very early in the morning before my kids wake up. I usually work pretty late after the kids are asleep. It is hard to do your best when you're working out at that time of day when you are operating under little sleep. Sometimes I feel like I am really pushing myself. My HRM lets me know if that really is the case. I check it frequently when working out and push myself harder when I notice my heartrate is not where it should be. When I used to take spinning classes, I found the HRM was really helpful.

Helps me to know whether i am working hard enough as I try to stay in a certain zone especially in spin class verses perceived effort which is often off.

I'm a data junkie and love my HRM. In fact I find it hard to exercise without it. It's motivating to me to see how many cals I'm burning.

I only used one while pregnant to make sure I didn't let my heart rate get too high. Unless you are geeky into numbers and keeping track of things, or have a medical condition, I don't think they're necessary.

I also use HR for biking/running. Other than giving you a more accurate calories count, I don't know that it is super helpful for yoga/gym classes.

I use mine for making my training most effective to improve my speed not for weight loss, but I can imagine if you are keeping close track of the calories you are eating, a precise count of how much you expend in exercise might be useful and the hrm can do that. I don't think I would bother with the expense for that purpose, but I can imagine some people do.

I'm moderately in shape. I use endomondo while running to track distance and time. Curious to know what yoga and gym classes are doing for me. Would love a brief "sell" as to why and how and when I should use a HRM to maximize weight loss. Thanks!