Oil breaks down depending on driving conditions and driving habits. Getting an oil analysis done is the only way to know the condition your oil.
What other people do isn't just like comparing apples to oranges, it's comparing apples to orange trees.
5000k would be a good time to change your diffs & transfer case fluids too. I waited too long at 20k on my '19 Ranger. All three were FULL of metal particles, so much so that the magnets on the drain plugs weren't collecting any more.
I put a magnet on my filter the day I bought mine. Cut the filter apart at 1500 miles and it had metal dust on the inside of the Did he/she mention the diffs & transfer case? I changed those fluids
IF you're being that diligent with your motor oil, which I commend you for, don't forget your...
I make my mind up depending on what's written on the filter and bottle of oil. I don't necessarily go that long, but that's how I judge it. Neither the engineer that wrote the manual nor the oil life monitor knows what oil & filter I'm using.
If the mileage interval isn't on the filter box...
Follow the Lanolin/Oil Undercoating Users facebook page. Tons of good info on there.
https://www.facebook.com/groups/1210804552884147/?sorting_setting=CHRONOLOGICAL
If you see cracks or its hard enough that you can't 'cut into it' with your thumbnail, I'd ask for a full refund, but that's me. Then I'd find someone who sprays the products I mentioned, on top it and keep your fingers crossed.
Also look for places its worn off, the frame inside wheel wells...
The dripping mess is why I avoided Rust Check & Krown. (I'm in Canada too lol). The Lanolin doesn't drip, but it does all the other things you mentioned.
There was no long term. Within a year it was full of small cracks, looked like broken eggshell. (which is death because these cracks hold salt & moisture and ends up being worse than having bare metal).
That is, where it was on at all. A lot of places it got sandblasted off from road dirt/sand...
I swore I'd never go down another oil or undercoating rabbit hole on a forum ever again, but here I go.....
Stick with a lanolin based undercoating. Woolwax, Fluid Film or Surface Shield. They stay soft & creep. They also 'self heal' which is your protection against the constant bombardment of...
It's a 50/50 deal for me. High speed off-roading isn't my thing, but having front & rear lockers is.
I'll wait and see if Ford offers a 6G Tremor in the near future.
They've done away with the Supercab too, disappointing. Not too many of us single men with no kids left I guess.