Date Malfunction

[Gebbeth]

Hello. I'm new here, so I apologize in advance if this has already been discussed, but I have a very old Rolex Day Date with Presidential bracelet...it's over 20 years old and was owned by my father.

He basically kept the watch, unworn, for a very long time, until recently when he decided to hand it over to me.

Once he gave it to me, I wore it now and then, but not as my everyday watch. I did, however, wind the watch each morning...about 20-25 rotations on the crown. I also updated the date when the months ended.

Now, I noticed that the date skips a day. For example, if today was the 10th, the next day, the watch would say the 12th...and so on (i.e., it skipped the 11th altogether). I can see if there was a malfunction that the date wouldn't move at all, or be 1/2 way from one date to another, but I was surprised that it would completely skip a date.

The day function works perfectly, and keeping time is also not a problem. It keeps, as far as I can tell, perfect time.

Any ideas what the problem is? I know I'm going to have to have it fixed, but I'm really wary of the cost. Is this a major problem or minor adjustment?

BTW, I asked my dad, and he's never had the watch serviced ever....so it's way past due, but I'd just like some insight into whether this is a common problem.