I just want something simple that I can attach to the windshield when I want
I have a very good experience few years back with literally the cheapest DashCam they had at a local store for US$47.
My recommendation is to buy it from a local store if possible as they could have it displayed for a demo so you can get your hands on it and experience it, see the suction cup holder. Usually the store should let you return or replace it if you are dissatisfied. Avoid buying unknown/unbranded products online or overseas as it’s a gamble, or at the very least time consuming to test them and return if even possible.
Based on your requirements and concerns, I can tell you this:
-The lower end/cheaper dashcams, usually come with the easiest and most basic mounting with a suction cup that wouldn’t leave any residue on your windshield. You can remove it instantly and it will look as if it was never there, and install it in another car instantly as well.
-It will plug in your car socket (cigarette lighter), so it can’t get any easier to hook up.
-It will always operate automatically as any higher end dashcam, without the need for you to touch any buttons i.e. once you turn on the car it will start recording, once you turn the car off, it will stop. This is assuming that the power in the car socket starts flowing only when the car is running, as it should be with most cars.
-Overwriting of old videos is a default (and only) option for any dashcam to operate. It will keep recording in a loop, replacing the oldest video with the newest one as you run out of storage, unless you disconnect it (or go into the settings to lock a specific video file). The length of the loop will depend on the memory card size you put in and the video quality settings you select.
-Night recording isn’t an additional option to have, once it starts recording, it will always continue regardless of. This becomes important based on your night video quality expectations. TBH, the cheap one I bought had bad video quality at night; however, as I was concerned about recording in the city/urban area, everything was well lit and you always have your headlights pointed ahead where the camera is recording, so it will capture anything in front of you. Simply said, the bad night video quality was satisfactory for my purposes.
-The cable is really easy to tuck in the gaps around the roof trim, pillar trim, dashboard and some creases to reach the socket. you can always leave it loose or hanging around, but I recommend looking up youtube videos of your car model for installing a dashcam, you’ll be surprised how many panels you can easily remove and put back just by pulling/pushing without any tools, and see all that space for cables behind.
For selecting and buying the dashcam, ideally find a mid-sized or large local store that sells and installs car accessories like stereo systems, etc. They will usually have a decent range of dashcams, and they will be more than happy to give you a demo of the actual device, or even go for a drive with you to try it out. Alternatively, go to the local Best Buy or equivalent at your location.
I got mine through a local store (equivalent to Best Buy in the US), first online I filtered the cheapest model they had in stock, I found reviews that weren’t rating it too high; however, on youtube I watched videos recorded with the exact DashCam model during day and night that showed me the exact video quality I can expect from it (you can try to zoom in licence plates, etc to confirm). It seemed decent for what I needed, so I picked it up from the local store and installed it. As a backup option, the store allowed free returns and full refunds if I would be dissatisfied.