Only necessary if you want one.
I think it is stranger to have them before term, TBH. It really doesn't tell you anything much - it can look completely different even the next day.
I don't intend to have any this time, unless I really want to know what's going on when I'm in labour. (That's the only time I had them last time - one when I arrived at the hospital, another to make sure I was fully dilated before I started pushing.)