Since you say it lasts a few days once wound, that implies if stops after more than just the base 42h - correct?

If so then the automatic works are winding the movement some, but not enough to keep the watch at a decent state of wind and hence running continuously. If this is a new thing (i.e. the watch is stopping or needs handwinding to keep running), then sounds like it needs attention.

If this has always been the way (and by “always” I mean when the watch was new or recently serviced and hence in a good state of repair), then maybe more jiggling is required, but I’d expect most folk be able to keep an automatic going.

How long has it been since it was serviced? A watchmaker should be able to put it on a timegrapher and tell if the movement itself is performing as expected and if not, that’s another reason to look at a service, but that is a separate concern to the effectiveness of the automatic winding.