Some charts are very generic and do not match real measurements at all. When it comes to eyewear, the small details really matter over time. I also check if the store explains how to measure PD and frame size clearly. Bad lenses can cause eye strain, reflections and headache when you wear them for hours. For light summer tops I keep to my normal size to avoid a baggy look. When every picture has different colors or extreme filters, it is usually a bad sign.
If anyone is interested in real user experiences, I sometimes write short notes about the shops I test.
You can find one of the pages here:
check this link
Taking a few minutes to research before buying can save a lot of money and frustration. Bad lenses can cause eye strain, reflections and headache when you wear them for hours. The main things I look at for glasses are frame weight, hinge quality and lens coating. For daily use items I try to balance price, build quality and real user feedback. If tracking never updates for weeks, I start to worry about the order.
Just sharing my personal feedback.