For light summer tops I keep to my normal size to avoid a baggy look. A simple pair of glasses or a basic jacket that always works is worth a lot. I like when they mention whether the fabric has stretch or not, that detail matters a lot.
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:
see more details
If a website gives a detailed guide for measurements, I feel more confident when ordering. This is why I like reading and posting on forums and community websites. I also check if the store explains how to measure PD and frame size clearly. It is always difficult to know which website is really trustworthy before you place an order. I think sharing honest feedback helps other buyers avoid the same mistakes. If you sit in front of a screen for many hours, these small features make a difference. I try to balance my budget between basic everyday items and a few special pieces. Forums, blogs and communities create a kind of collective memory for shoppers.
Hope this helps someone.