Find the month when owning it costs least, and whether to keep or replace what you have now.
What are you looking at?
Currency
Cheapest to own if you keep it about 5 years 5 months
€17 per month
About €17 per month all in (what you lose in value plus upkeep).
Months owned
3 years 4 months – 7 years
Within 10% of that from 3 years 4 months to 7 years. Selling much earlier costs noticeably more.
Average cost per month of owning it
Resale value against what it has cost you
Months owned
Upgrade less often, invest the difference
If you replace it every
instead of every 5 years 5 months
That saves about €9 per month.
Invested at 6% a year for 10 years, the saving becomes €1,544 (you put in €1,131).
Already own it? Keep or replace now
Keeping it 12 more months costs about €154 (€13 a month).
A new one at its best costs about €17 a month.
Keep it: the old one is cheaper to run than a new one would be.
This compares money only. If a new one gives you something you really need, that is a separate decision.
Defaults come from public depreciation data (Carfax: about 20% lost in a new car's first year; iSeeCars: about 46% over five years) and are only a starting point. Check real resale prices for your model.
An illustration, not financial advice. Real prices, rates and fees differ.