Have a 2008 Isuzu Ascender RWD which is a Chevy Trailblazer with a Isuzu name on it . Has 140000 miles on it and still runs great and doesn’t burn any oil between 6000 mile oil changes . Body is still in really good shape considering it has seen 8 upstate NY winters and tons of salt . I have taken good care of it but am considering trading it in on a new 19 Dodge Durango RWD . I DO love the I6 in this thing,smooth and powerful if a bit gas thirsty at 22 mpg. Highway . Should I run this thing into th ground or trade it where I may get $3000 if I’m lucky against a new one . Most everything is still original except shocks and front struts which were done at about 90k and the exhaust manifold which was done around 100k under extended warranty by Isuzu/Gm for free for a known issue on said manifolds . It does also have newer ceramic brakes all the around and newer serpentine belt with maybe 30 k on it .
I honestly don’t how anyone can make that decision for you . I don’t know if you have someone who might be your significant other but if there is then that is who you should ask this question .
frankly myself I would not have anything to do with the Fiat / Chrysler mess.
Is it paid off? you are investing in depreciation or repairs. If it is paid off assuming $500 a month for the new vehicle so that is 6 grand a year. Now 6 grand a year can cover a lot of repairs, but then do you have the time to do those repairs. I am 2 sided, I want my wife to have a dependable vehicle for road trips to see her mom etc., so she gets new, me I am mostly around town, and if the thing blows up on a road trip as I now have 200k miles, a day or 2 in a motel and buy something else. There is not a single answer.
Really depends on how bad you want the new ride and how much disposable income you have. Sounds like what you have now is reliable transportation. But a new ride is always nice. Since you’re kind of on the fence on what you want to do, you might set aside the money you’d be paying on a car payment for a couple of months and see how bad you miss that money. It might make the old car look better! 
. Or you may be just paying cash for the new one. Not a lot of folks do that, though. If you still want it after a cooling off period where you’ve saved a little, I’d say go for it.
You sound just like me . We do a fair amount of car travel and my wifes 2014 Dodge Grand Caravan now has almost 90000 miles on it . So I am debating whether having 2 cars over 100000 is smart or not . I am also debating whether to just trade hers in on a new one too instead of mine . Mine has to be able to tow a 4000 lb boat for shorter distances too . I dont do any real long distance towing just to the marina and back and putting the boat in and out . Hers will be do for a tuneup soon . Replacing hers would be about 8000 less .Durangos are nice but are they 32K nice 
. yes both cars are paid off .
I wouldn’t even consider trading this Izuzu. It should have plenty of miles of good service. You have kept up the maintenance so get the return on what you have spent on this vehicle. Don’t give it away to someone else.
Please understand that I am a tightwad. If something still functions well for me, I don’t replace it.
I drive new cars every day at work, it is nothing special for me so owning a new car wouldn’t give me the same experience as it would to someone else.
If you drove this vehicle for a year and there was a major failure you could give the vehicle away and forget about the $3000.
If you buy a new SUV you could collect the $3000 trade in value but would experience $7000 in depreciation in the first year on the new vehicle.
My attitude is why trade in a good, running vehicle for something else, and spend a bunch of money to basically do the same thing you are already doing now? There’s nothing magical about a new car, despite what the marketing people would have you believe, and the excitement of a new car wears off long before the payments are finished.
You have a paid-off SUV, which apparently still meets your needs and runs fine. The Trailblazer was a very reliable model, so if your Ascender is really just a rebadged Trailblazer, it should be good for a long time. Unless your Ascender has rust or body damage, I would continue to drive it until it no longer runs.
I’d continue on with the proactive maintenance and otherwise drive that 'lil puppy until the wheels fell off. Seems like a very good vehicle.
My wife has an 07 Lexus with over 220k miles. She LOVES the car. Runs great, been extremely reliable. We have no intensions of getting a new vehicle. We can easily afford a new vehicle, but WHY? It’s not how much you make, but how you spend it.
There’s also nothing magical anymore about a vehicle hitting the 100K mile mark on the odometer. The last several vehicles I’ve had we kept well into and over 100K miles.
True, stuff tends to break and/or the are maintenance costs involved, more so that a new(er) car. But they’re also paid off, and you can plan for the maintenance cost.
I always go back to: is your current vehicle reliable, and does it meet your current and expected future needs? If so… why get rid of it?