Tacoma

Anytime you can afford to but you probably owe a lot more than it is worth.

What if it's an older truck? Worth less than the one I have now?

You can trade it in anytime you want. The issue is, what you paid for your truck vs what the dealer will give you for it will be much less. Go onto KBB.com to get a trade in value. 20% less than what you paid in most cases. You will still owe the original amount and the dealer will then add it into the cost of the new or older truck. the issue with be now you have negative equity....https://www.thezebra.com/insurance-news/2946/what-to-do- when-you-owe-more-on-your-car-than-its-worth/

Use online valuation websites to find what your truck is worth and compare that to what you owe on it.

I would try to sell the car yourself through craigslist or local papers for around what you paid, and once you get the cash in hand start looking.