What is the best time (mileages) to trade in prius c 2013?

It’s true that the 2013 Prius c doesn’t have advanced driver assistance systems such as Toyota Safety Sense, but I wouldn’t underestimate the value of its safety features: not only the SRS airbags, but also a brake system with ABS, TRAC, and VSC, and a body with impact-absorbing structures.

I imagine only Toyota, has enough reliability data to answer your question properly, and for obvious reasons, they don’t publish it.

You can see the possible effect on trade-in values of waiting, however. For example, at this writing, Kelley Blue Book’s estimate for a 2013 Prius c with 135,000 miles is about $3,700, and for a 2012 Prius c with 160,000 miles, about $3,300. These figures differ with location, condition, and equipment, of course, but in this example, adding a year and 25,000 miles reduced the value by only $400 or so.

Since your current car seems to be in good condition, I’d suggest to wait at least six months before even considering a new one, and meanwhile, to save what you can for a down payment or unexpected major repairs. By then, you’ll know whether your new job is working out, and Proposition 22 will have succeeded or failed, making it clear what kind of future Uber and similar companies will have in California, and whether you would still have enough flexibility and earning potential to continue as a driver.