He isn't getting the opportunity to learn which instincts are actually good ones.
If he wants to use a meter fine, but its 10 bucks I wouldn't spend on something I can literally do myself. Modern tech is great, ph meter, ppm etc etc. Those are important, the exact water content of your soil is not.
I find that a meter is inhibiting as far as time is concerned as well.
Those small fuck ups are the reason I am a good grower now or did you not read my post? I learned very important things very early due to fucking up but catching myself before the fuckup became really detrimental at all.
People have been growing dank weed without moisture analysis for thousands of years. The exact correctness of water content could even be possibly detrimental because it leads to over caring for the plant.
I am not saying I am right, I am just saying it is unnecessary and if you pay attention to your plants through out the day a few times (I know I can't stop myself from gazing in my room anyways so its not a big deal) you will notice that they change slightly as they cycle through the conditions you give them. You will quickly see the difference between an amply watered plant, a plant that is growing in medium saturated to field capacity, and a plant that is too dry. It is worth watching it happen atleast once especially if you are a n00b and looking out for the issue so you can correct it.
Then you would always have the knowledge that that is a bad look and what you need to do to get them to look happy again.
Get a meter if you want the result will probably be almost the same but it is 10 dollars I don't have to spend on something unnecessary.
Edit--
The second guessing yourself through your first grow is the second thing I attribute to me being as good as I am now. Second guess yourself a ton and you probably won't end up doing anything drastically wrong. If you are second guessing yourself ask someone who knows better. A machine isn't going to have a conversation with you and you can't be sure your meter isn't lying to you unless you feel it for yourself anyway.