Having a map book, and using it, is important in my opinion. I’ve got the Phillips Navigator one.
I rely on my satnav for on-route guidance, but every time I set off to go somewhere I don’t know the route for, I look over the route in my map book first and compare it to the route the satnav wants me to take. 9/10 times they are the same, but there are those occasional times where the satnav wants to route me, for example, off the motorway at junction 20 and then follow an A road through a couple of villages to the delivery point, but looking on the map you spot that if you stayed on until J21, you can be blasting along flat to the mat, and only do a short stretch of A road, then you reach your delivery point from the other side. You might add a handful of km but knock a decent chunk of time off.
It’s also amazing how just following your satnav can leave you stuck in that mindset, without any real awareness of where you are.
I had a demonstration of how important that is just last week - One of the old hands at work who’s given me all sorts of top tips, had told me to always keep count of what junction you’ve just passed “just in case” and I’ve been trying to do it as much as I can, though of course laziness does kick in from time to time. Luckily last week I was on the ball. I was northbound on the A74(M) and saw a car in the southbound carriageway, for no apparent reason, spin out and give the barrier a couple of ■■■■ good whacks. 2 women in the car looked very shaken up, but okayish, and they were stranded in lane 3 - a very scary and very dangerous place to be. I phoned the police immediately, and was able to tell them that it happened about a mile or two southbound of J18 - how else can you tell the emergency services where something has happened on the motorway, without using junction numbers? (In the past, I’ve tried telling them the milemarker code, when I drove past a car that had dumped an engine’s worth of oil across all 3 lanes in the wet, but they didn’t know what to do with it.) Anyways, within maybe 5minutes, tops, of making the call, I saw a police car shoot past southbound absolutely flat to the mat. So help and a bit of safety was on the way to those two unlucky ladies asap. If I wasn’t paying attention to my surroundings, the only way I could tell the police where the crash happened would have been to keep driving on and make them wait until I found the next junction… and that can take a long time.
Google maps is great, in satellite view, for spotting exactly where your delivery or collection point is. The map book is great for route planning. The satnav is great for on-route guidance. Using a mixture of the three is, to my mind, just common sense.
Also, if you miss a turning, do you blindly trust your satnav to unf**k you, or do you find somewhere to pull over and check the map? I’ve blindly trusted it before, and ended up doing a loop around a tiny one-way system that had me pouring so much sweat I looked like I’d been standing in the rain. It was doable, sure, but what I should have done is pull over, check the map and I would have seen that if I’d gone only a little bit further on I’d have come to a big roundabout and could have just looped around without any drama, but the satnav wanted me back on the route in the shortest distance possible.
I’ll stop rambling in a minute, I promise!

My final point is that reading a map is easy, if you’re used to it. When I was young I went through the whole Beavers and Scouts thing, so got used to reading a map. When I started driving, I’d not read a map for about 13 years or so and it’s not half as easy when you’re rusty, you’re in charge of a lorry that you can only take down certain roads, it’s dark/raining/both - so it pays to get used to it so that it’s natural because in this job, the only time you will absolutely need to read a map is when you’re up ■■■■ creek.