First of all, I'm based in Northern California. Pull up your favorite online map of the area. Our roads are hardly based on anything resembling a grid system (inner cities & the Central Valley being exceptions to the rule).
Secondly, I've traveled to England four times in the last three years. I have borrowed cars and motorbikes from various friends on each trip. I haven't had issues getting to where I needed to go using plain old maps.
Thirdly, no, I don't need to have the map open and in front of me while I drive. It's not exactly difficult to memorize a route. (Do I detect a hint of the Nintendo/MTV Generation's "If it's not constantly changing, I'm not interested in it" here?)
I wondered: "Why not ask the client for driving directions?"
Several opined variations on: "Choose your option:"
" Because it makes a stupid impression?"
Why. Do you honestly think "I haven't been there recently, how long should I plan on it taking from when the freeway enters your town to when I arrive at your office at that time of day" makes you sound stupid? To me it's an intelligent question.
"[1b] Because things get really awkward if the client doesn't know and feels put into place?"
In that case, the correct answer is "I don't know ... Let's find out!", and then both parties relax the rules on scheduling a little. Works for me :-)
" Because the client doesn't necessarily know the route, from your last client to him?"
If you are using maps, you know the general route you are taking ... and you will know when you will reach a built-up area, where guestimation is pointless without local knowledge. I'm not suggesting asking about the route from Leeds to London, I'm talking about asking for local info once in London (which I don't need, BTW, despite being a Yank).
"[2a] Because the client has the same chance of knowing the route from you to him as you have?"
Meaningless. I can easily get between two built-up areas using maps. This has been true on six contenents, over 40+ years (I hope to get to Antarctica eventually). My clients have, over the years, ALWAYS been aware of local traffic patterns (with a couple exceptions, see below) ... and more than happy to assist me in traversing their area. Remember, it doesn't just save ME time, it also saves THEIRS.
" Because even if they know a route, they're not necessarily good at explaining it?"
'whole 'nuther kettle of worms. Has happened occasionally. Always with Doctors and Lawyers. By personal preference, I no longer work for Doctors and Lawyers. Problem solved.
"[3b] See 1b?"
See my answer to 3.
" Because there's more travelling to be done than just to clients in this world?"
If you are not on a schedule, relax. Get lost! Enjoy it! Stop and have a cuppa (or a swift half) while figuring out where you are with respect to your intended destination. The destination will still be there when you get there ... and if you do get lost, you'll have been lucky enough to see more of this dampish rock than most people do!