I think it’s horses for courses, mate.
Because you travel from A to B on a regular basis, sometimes to C and occasionally to D.
You know the route already.
When you get thrown a curve ball…“Oy, you, take this to E”.
It’s easier, and cheaper, for you, to get the map out and check the route for things to be aware of, bridges that jump out at you, widths that squeeze yer erse, greasy spoons that serve proper english breakfasts with fried bread (Had one today, Cafe Royal, opposite asda, park royal, a thing of wonder for 6.75 
) You already KNOW how to get to E, you just need to check the route for safety.
Doing this on a regular basis means you know the route already, and if you don’t a quick check will put you right.
Don’t buy a satnav
But for blokes like me, puddlejumping, multi drop, central London and surrounds, a satnav is absolutely invaluable. I could not, would not, do the job without it tbh.
It takes 30 seconds to put the next drops postcode in and go. On an A-Z would probably be a couple of minutes to find it, then move off. And that always assumes that you have a half competent co-pilot to map read you to the drop. No, def not happy with THAT idea.
Doing that 28 times a day would possibly cost a shed load more time. I’m not averse to a bit of OT but I’ll do it when I WANT to do it 
Buy a satnav.
Anyways, you’ve got one 