Lifespan of a flash drive on MR-3020 (OpenWRT)?

Question

Do it yourself

Help roughly calculate the life of a flash drive as an OpenWRT system disk on the MR-3020. The device collects data from 2 sources, writes to a text file (300 B) and uploads an xml file (4.5 kB), then the data is loaded into the SQLite database, with an interval of 5 minutes around the clock. USB flash drive 8 GB. Based on the volume without rewriting the flash drive, it should last for 8 years. The problem is in the overwriting cycles.
1. I would like to find out how long the flash drive will live under such conditions.
2. What affects the life of a flash drive - write to one file or different ones; buffer data and write in one operation or line by line; flash drive type (usb, sd class 4, 6, 10, etc.); to write in a DBMS on 1 record or transaction?