I often get asked how long a pet portrait takes to do and the answer is it varies. It depends on several factors like the quality of the photos, how much detail in the dog's markings, if a horse has a bridle or complex markings.
Because I am also a Music Tutor and Musician I might have to go off and do some lessons or work on some songs for upcoming gigs. As well as that there is admin to do - bookkeeping, website updating, marketing and social media updates. All of these take up valuable painting time, but to be fair this is probably not a bad thing because after a break I'll come back to the painting with a fresh eye and see details that I'd missed like proportion or eye shape.
I once did an art business course and was told that only a third of the working week was actually spent painting, I'd say that is about right. Also of course there is spending time discussing what the client wants and sending out order forms. Sometimes I will even go out and do my own photoshoot of a horse, dog or cat. I used to regularly take my own photos, but that doesn't happen much in this day of camera phones and email!