When to test?

Natjs hi I usually test before meal and two hours after but test more if not feeling well or think my sugars are a bit low hypo. PS I'm type 1 so not sure about type 2?

Yes, test just before and 2 hours after. Do this for random meals to find out what foods affect you most.

You can test whenever you like as long as you test immediately before. The only guidelines from the NHS are "at least 2 hours", which is why most test at 2 hours. That time is intended to show how your pancreas is working. Most meals will spike at around an hour to 90 minutes, so by 2 hours you should be on your way down. Not all food combinations work this way - the more fat, the longer it will take to come down but the lower the peak will be. Just keep records.