I had a 2017 Yaris Hybrid and never had any problems with the 12v battery losing its charge, even though I only drive around 3,000 miles per year. In May 2021 I upgraded to the latest version Yaris. It is a lovely car but in February 2022, after standing in my garage for 5 days, it failed to start due to a discharged 12v battery. A quick call to Toyota Recovery resulted in an AA technician arriving to give me a jump start. He advised me to run the car in "Ready Mode" for an hour every week or so to prevent anymore problems. Also said that I should get my Yaris checked by my dealer. I did this and they found no problems but they did sell me a smart battery charger. So far I haven't had to use the battery charger but have followed the "Ready Mode" advice. No 12v battery problems since but feel that this is a problem that Toyota should be looking into considering the many reports from others having the same problem.