While warranty is not the first thing we look at when selecting cameras, a 1-year warranty does not instill much confidence in a product. All things being equal or similar (resolution, sensor, options, etc.), we will always go with the camera that has a longer warranty period.
It also helps if the first year's warranty is over the counter at a place like ADI. Hikvision and DW, from my experience, are pretty good at the OTC warranty replacement and it allows me to keep my people installing equipment instead of filling out more paperwork.
1, that's a good question. 2 has an informative response.
It is pretty rare now for camera manufacturers to offer less than 3. Axis famously did only 1 with their M series for years but recently bumped it to 3 years.
Beyond that, as 2 mentions, there can be some differences on advance replacements. Also, some manufacturers give longer warranty terms (I believe Hikvision has 5 years for top tier partners, someone correct me if needed).
There, of course, is also issues of failure rates. Failure rates are not as much as a problem as they used to be. While issues certainly can arrive with specific runs and specific parts, it tends not to be a major differentiator amongst most well-known brands (spam sellers differ).
Also important are the exclusions. Is the warranty period the same for a PTZ, including the moving parts (lens, PT mechanisms, etc.)? What about hard drives in DVR/NVR? What about a DVR/NVR that you put your own drives in to - does that invalidate the warranty of the recorder?
I have also heard that some PTZ cameras will change the warranty depending on how you use them - if they are in auto pan mode for a certain period of time, a counter or fuse trips to indicate a shorter warranty.
As a further dialog, here is an example of a 3 year warranty, that has exclusions of 1 year for many components (imager, HDD, fans, PTZ mechanisms, etc.) and a 3 month warranty if continuous auto pan is EVER used on PTZs. I mean come on - a PTZ that you aren't supposed to PTZ with...
(I believe that some of this has recently changed...)
ACTi's warranty term is quite dynamic, ranging from 3 months to 3 years, as shown by this matrix:
More than occasional PTZ use may reduce your warranty by 33 months (3 years - 3 months). Indiscriminate and inappropriate zoomers beware.
Panasonic recently went to a 5 year advanced replacement warranty on all cameras
We found the following information for the top 10 North American Brands
1) Axis - 3 year
2) Hikvision - 3 year
3) Panasonic - 5 year
4) Hanwha Techwin - 3 year
5) Avigilon - 2 year (unconfirmed but disclosed above)
6) Sony Corporation - 3 year
7) Pelco by Schneider Electric - 2 year /3 year
8) Bosch - 1 year PTZ / 3 Year
9) Dahua - unconfirmed
10) Arecont Vision - 3 years