does anyone here train regularly at more than one dojo? that is, visits each dojo at least once a week, or a few times every month?
if so, why do you do this?
By this criteria, I'm usually training at three dojos.
We have classes five days a week. If I wish to train on a Tuesday or Sunday, it means visiting another dojo. On Sundays, I'll go to another ASU-affiliated dojo, that's about fifteen miles away. On Tuesdays, I often go to an Iwama-style dojo that's about a half mile from our dojo.
The other ASU dojo, Aikido Shobukan Dojo, has more higher ranking students than we do and is also where my instructor went for fifteen years. (He still goes there on occasion and still teaches on occasion, as well.) We've always been encouraged to go to classes there when either we don't have class or a scheduling conflict means we can't make it to our class. (They have morning classes, which we do not.)
The Iwama-style dojo is a bit different. I started going there on Tuesdays because I wanted to get a class in on Tuesday (that was closer) and because I like the instructor. I've never thought of there being a question of loyalty. My instructor knows I go there and often asks how things are going there. The instructor there has always made me feel welcome. Both instructors have asked me, on occasion, if something is done differently at one place or the other. I find that if gives me a different insight on certain techniques.
or you more likely to end up confused and unhappy?
It depends on what is different and how different it is. For example, I'm not sure I'd want to do too much weapons work at the Iwama-style dojo, because it's different than what we do at our dojo.
On the other hand, more techniques there are done from a static start and I find that helpful at times. I did not start training at the Iwama-style dojo until I had been training a couple of years. It might have been pretty confusing if I had started earlier.