Weeks versus months

Just curious, when did you mamas stop referring to your baby's age in weeks? I would say baby is 8 weeks, 10 weeks, but after 12 weeks, I switched to months. So at 14 weeks I didn't say 14 weeks, I said 3 and a half months. Just curious, no right or wrong answer here. I just see a lot of posts that say something like "my 19 week old" versus my almost 5 month old.