I've been monitoring for the last 8 months using the mysugr app, i've integrated this into my excel workbook to find in detail how my insulin to carb ratios change through the day.
I've logged everything from my blood test meters in excel for 7 years now. My data has given me my daily blood sugar cycle, and what i did look into just recently was the longrun seasonality. My blood sugar has an annual cycle too (see graph).
What is great about android/apple apps if you always have your phone with you is it gives a superb overview of your day by day management, a good tool for logging carbs,insulin and blood sugar results, then you can quickly make changes and view graphs on your phone.