Battery lifetime and lifetime of other components?

It's tricky to give exact figures - the best thing to do is measure. I put a double-sided flexi PCB between the battery and the board, and measure the current draw.

• It's roughly 20uA when advertising, so a bit over a year
  
• It's roughly 3uA when not advertising, so potentially 5 years or so
  
• When watching a button and not advertising that raises to 12uA, so it's still around 2 years
  
  

Kingbright don't give lifetime info for their LEDs, but it's a lot. They're high quality and only run at 1-2mA so not stressed.

In terms of switch lifetime, it seems to be around 50,000 presses - so if you pressed it once a second for 24 hours a day then it might start to get a bit dodgy after 6 months.