Im building a bedside alarm clock/home assistant. I have a few buttons that input, an LCD display and some RGB LEDs. The LCD and RGBs are only on when commanded to be on. I was wondering if I could leave the mega plugged in and constantly running or if that would burn it out. Im a bit new to this so sorry if this is dumb. If it would burn out, how long is its lifetime?
As long as you operate the electronics within specification they will run for years and years. The first thing to probably fail will be the electrolytic capacitors that will dry out after maybe 10 years.
When reading datasheets and specifications the metric you are interested in is the MTBF - the Mean Time Between Failures.