A standard men's haircut runs about 20 to 30 minutes for a scissor cut or fade — roughly the same whether it's a shop chair or a mobile visit at home. A simple buzz cut with clippers alone is faster, usually 10 to 15 minutes. Add a beard trim or a hot towel and expect another 10 to 15 minutes on top of the cut.
What actually varies isn't the cut, it's everything around it. A shop visit means driving there, finding parking, and often waiting behind whoever got there first — easily another 30 to 60 minutes before the clippers even turn on. A mobile visit starts at the scheduled time, in a driveway or living room, with no queue to sit in.
Total time is the real number worth comparing: a 25-minute haircut that costs you 90 minutes door to door at a shop is a 25-minute haircut and nothing more at home.
A few things that add time either way: longer hair takes more scissor work than short hair, a detailed fade takes longer than a simple taper, and a first visit with a new barber runs a little longer while working out exactly what you want.