Hello, it looks like the 3 batteries won't last long. I have been using the alarm clock since the beginning of November. The automatic light is on. The last bar of the battery indicator is lit, which means that I will soon have to replace the batteries. I will now use rechargeable batteries. I only discovered the battery charge indicator after your question. Otherwise, the alarm clock works perfectly. Greetings from Valais

Absolutely reliable for 15 months so far.

Unfortunately, I can't answer that because I haven't tried it.

I can't say, I only switch on the light briefly via the push-button. Probably for a very long time, because it's LED. It's the best alarm clock I've ever bought!