I have been using Nextion enhanced displays with CR1220 coin battery on my projects. Do you know that, how long does it consume to battery? I used to ds3231 modules with arduino, but its batteries had been consuming about in 1 months.
in general, the battery lasts until the battery is empty ... :-)
seriousely, it depends on many different factors ... there is no exact rule about ...
Actually, I want to that It work for least 2 years. Otherwise, I must change to battery often. Its mean is sending service car, more and more cost for only a coin battery.
(If my sentences seems like bad, I am sorry. I had to use google translate.)
cr1220 is only the size and voltage
- how much charge it contains can depend on age and manufacturer
Your outlook is wrong as well
In today's world, when do you get free service car?
(not expense, but small revenue generated because of little battery)