My 9 year old Sigma bike computer is about on it's last legs. I'd like to buy a new one that will allow me to input my current miles into it so I don't lose them. Can anyone recommend a bike computer that will for sure allow for previous miles to be input into it?

Cateye Strada.

The only ones I've found that do NOT have this ability is some of the less expensive Cateye models. I bought whatever the cheapest Cateye was that the LBS had and it didn't have the ability (confirmed by the LBS owner when I returned it for this reason).

Oh, and the $5 chinese ones won't let you set a mileage over 9,999 miles.

I have an old wired, Sigma BC9, on my hybrid, that cost me around $25.00 and it allows me to add miles into the odometer setting. I think any of the Sigma's will do that, but I would go online and check out the spec sheet of the one you're interested in to be sure.

That was my experience. I bought a cheap Cateye off of Amazon. It didn't have this ability. It was going to cost almost more to ship it back than I paid for it.

I should say that I don't know for sure that the more expensive Cateye models allow presetting the odometer. Only that the cheap ones do not. PDF manuals should be available online, read them and confirm functionality before buying.