Heart Girth Cattle

I was wondering how many of you have heart girth cattle.  Our scale is very old and it hasn't worked a few years. Every time we start talking about how much a calf weighs  Dad brings out the old heart girth tape. How accurate are they and are they used much any more.

we don't have  a scale so I use one,  I try to get a starting weight when we buy a steer, then I use the tape at the same time and figure out what figure I am going to use.  I change my figure as the calf grows and changes and puts on fat,  I will also use the tape before we weigh in somewhere I am usually within 5 pounds