Update:
I decided to do a battery monitoring system calibration on my tablet and phone. I couldn’t remember the last time I carried this out……… So I discharged both devices to zero until they switched off, then fully charged them to 100 percent. I had an energy meter plugged into the power supply to measure the milliamp hour capacity.
This time my tablet recorded an 8 percent degradation, and the phone was 13 percent.
I’m happy with that. The tablet is almost 4 years old, and the phone is 2 and a half years old.
My phone is switched off overnight, but it is still on for around 16 hours a day. Even when idle a mobile phone is doing lots of unseen things in the background so it is still undergoing use.
Personally I think that around 5 percent degradation of my phones battery per year is very reasonable, and this is thanks to Chargie.

However, my mobile phone (Xiaomi Redmi Note 8T) shows different results after two and a half years. The battery degradation appears to be between 20 percent and 35 percent. It varies each time I measure it. I haven’t measured from zero, around 10 percent to 90 percent is the most I have done, and then proratered the results to equal 100 percent capacity.
The phone runs hotter than my tablet, but rarely exceeds 30 degrees Celsius. I have the temperature limit set to 35 degrees.
Again, I do not let the phone discharge too low. Around 35 to 40 percent is when I start charging, and I have the Chargie set to 75 percent, or sometimes 80 percent.
The battery degradation seems quite high considering I have been using the Chargie, but I am not too sure about the accuracy of the capacity results.
Also although the battery is a nominal 4000 ma/h, I cannot be certain that it was that when new. If it was less then this would give a lower degradation result than my calculations.
The battery still gives me about the same amount of usage in between charges as it did when it was new. Typically I charge to 75 percent and with my light usage this will last 2 days before it drops to 40 percent. This is a bit subjective but the battery still appears to have the same runtime as it did when new.
So, has my phone battery degraded by 20 percent, 35 percent, or very little?