Ranger Mods

As per the title, just want some opinions on when to do your oil changes?
Do you do it at a pre-determined mileage /Km or do you wait for the truck to tell you it wants doing?

I'm sure I read somewhere that the interval is 20k miles but can't remember where I saw it.
When I bought my 2016 ranger it had approx 58k on the clock, not long after owning it I got the "change oil soon" message on the dash, so I did. (did the oil life reset) Then 10k later, I changed it again but did not reset the oil life monitor. She's now on 73k ish and the "change oil soon" message is back (this is only approx 5k miles since I did the last change. By my reckoning thats 15k between the first oil change warning & the second.

So should I do it once only every15k or do an interim at 7.5k? Thoughts & comments welcome. (Even if it's just telling me I'm overthinking it!)
I live in the UK at sea level, so fairly mundane environmental conditions.

Thanks, Clayton.

Whatever the service book states.
15,000 km general driving, 10,000 km for heavier driving. More so would have been based on now using fully synthetic oil.

Some will always do 10,000 km as they have always done 10,000 km in previous vehicles. Some will even do 5000 km. That may be based on because I was told or I heard or my Dad did and not from testing the oil but 10,000km is fair. I have pulled mine back to 10,000 km because I drive harder than nicer.

You have mentioned miles and km or k many times so I'm unsure what measurement you are really using.

For transmission I would ignore the book and do every 50,000 km at the very most.

My service books says every 15,000km, but I don't personally like leaving it that long. If it was 15000km of highway driving then fair enough, but mine gets a good mix of driving. It does some highway km, but it also tows a 3T caravan and does it's fair share of slow speed stop/start suburban driving, neither of which are great for engine oil. I opt to get an intermediate oil change done every 7500km just to be safe. It also means I don't run the risk of ever getting the "you must change you message" on the dash.

"You have mentioned miles and km or k many times so I'm unsure what measurement you are really using."

Hi Stewart, sorry for the confusion, I'm in the UK so it's miles, I used the "k" to indicate thousands (of miles) not K for kilometers

Think i will settle for every 7500 miles. Can't actually find anything in the handbook that states how often, just how to check & top it up. (Guess ford expect you to take it to them)

Change the oil as often as you can afford to. A tip from an old engine builder years ago. Mine gets done every 7500km.

or

I'm mentally lazy and its easier to do the math and an oil and filter change every 10,000 kms rather than say every 15.000 - as in 10,000, 20,000, 30,000 etc and I'm now up to 140,000. I look on eBay and Facebook for "specials" and for example recently I bought 15 litres of Castrol Edge 5W30 for $135 saving roundly 50% of the normal cost and some time back when SCA had a special deal going I bought 3 Ryco filter kits for $75 each, a saving of $38 per kit.
I have a 30 litre oil drum in my man shed and all unused new oil goes into it, roughly 1.5 litres per 10 litre container, and I estimate that by now I have enough oil in it, at least 20 litres, to do two complete oil changes without having to buy any.