Normal to do group gift for every coworkers new kid/wedding?

This has been a tradition at my current shop since I've joined and I've always contributed. Whenever someone on our desk has a kid or a wedding, we will each put in some money to give a group gift to them. Now, I am both child-less and wife-less so I have not been able to take advantage of this, but I have probably contributed to 10-15 of these over the few years I've been here. 

Recently, I brought up the practice with a friend and he said it hadn't been a thing at any of the firms he had been at, so wanted to ask WSO if it was normal? Tbf I get along with my coworkers so don't mind and it's not much each time.

The only thing is that I'm never sure how much to give, and it's the MD who collects it via his venmo so he knows exactly how much each of us give (I don't think this changes how he views us, but he definitely internally makes a note).

Not to mention, one time it was a colleague who we didn't particularly enjoy working with so a few of us didn't send anything and he made sure to message/talk to each of us asking if we "missed the email" so we ended up having to send something).