Soo ladies... I caved. I bought a doppler, is there really any harm using one once in a while?

I understand it’s not okay to use all the time, but I mean once in a while is okay right? I never got the chance to hear my baby’s heart beat during my previous ultrasounds, and it’s been almost a month since I’ve seen my babe. I still have to wait until the 24 for the detailed ultrasound and I doubt they will let me listen then either, it’s something I’ve always wanted to do, I just want/like the security to be able to listen to my little ones heart. I’m at work all day by myself And it’s driving me insane because I want to listen, but again my hubby will be home later tonight around 8:30pm and it’s 12pm 😩🤦🏼‍♀️ would it be real bad if I gave it a go now and a go later then not again for at least a week or so? Idk I see mamas do it all the time, but then you get some people saying it causes so much harm..? The reason I never get to listen to baby’s heart beat during ultrasounds is because my technician said it’s too much on baby to have the ultrasound and listen at the same time. Idk did u just waste my money? Thoughts..?