My iPhone cellular data is typically well under 3 GB a month. Mostly because I’m usually at home and using wi-fi.
But the last two months my cellular data has exceeded 7 GB a month.
Upon first check, it appears that “system services” (mostly syncing Desktop and Documents) was using most of this data. So I went into Settings > Cellular and turned off syncing over cellular data.
That slowed things down, but I still wonder - why? It’s never happened until recently. And why would cellular data be used for that all of a sudden since my iPhone is on wi-fi most of the time?
There is some cost impact to this. About 6 months ago I switched to the new Softbank “Merihari” plan, which gives me unlimited 4G and 5G data with no slowdown at a lower cost than my previous 5 GB plan. But that plan also includes an extra 1,500 yen/month discount if my data is below 3 GB/month. The first few months that was the case and my month bill dropped from about 10,800 yen/month to 7,500 yen/month.
But last month and this month I didn’t get that discount, so my bill was about 9,000 yen. Still a savings over it was before, but a waste of 3,000 yen for some unknown reason.
Any idea why my iPhone could be using so much cellular data?