TITR or Time In Tight Range also simply called Time In Range (TIR) is the way that people who use Continuous Glucose Monitors (CGM's like Libre and Dexcom) track their blood sugars

Standard "range" for most diabetics is considered to be between 4.0 and 10.0 mmols or 70ish to 180

Staying in that range "delays" the onset of diabetic complications for about 10 years

If you want to keep the beast away then you need to follow a "tighter range" - in my case that is 4.0 to 8.0 mmols (70'ish to 144) because we do vascular damage to our system if we spend too much time above 7.8 mmols or 140 points

If you can stay in a tighter range more than 70% of the time you will lower your chance of developing complications. If you can stay in range over 90% of the time you are "unlikely" (have done everything possible) to never see a complication and it is the complications, not the Diabetes, that takes us out (Diabetes is not fatal by itself - it messes other stuff up like our heart and kidney's that do the job)

Hopefully one day we will all be using CGM's to manage - they do give immediate feedback

My Libre2 takes a reading every "minute" - the equivalent of 1440 "finger sticks" a day so never have to guess what my blood sugar was up to and the app/software calculates "how long" I was in range for the past day/week/month/3 months