I have a pigment ink printer, Canon Pro 1, and I leave mine on all the time. I believe they do run cleaning cycles at timed schedules, but I also was concerned about clogging. Sometimes I just do a nozzle check if I'm around and haven't printed for a few days.
I have purchased Qimage1 which allows me to schedule a print purge pattern when I am away. I have to leave my computer on too for this. If you are away on holiday then this does mean it will print unattended and there is the possibility of paper jams.
Another alternative might be to leave your computer on and use a remote software to send something to the printer. This means you can print something useful and not just a purge pattern. I haven't tried this.
There is an awful lot of info on this Youtube channel
https://www.youtube.com/user/cheo1949
If you do come across a macro, I'd be interested too!