As someone new to keto, I’ve been testing quite a lot.
There are days when I only test once during the day, but on most days, I’ll test at various times to see where I’m at. I will often test before/after meals and/or before/after exercise. I know now, for example, that eating a “low carb” energy bar is not an especially good idea due to the fact that it’s not quite low enough in carbs - or so I surmise - another possibility is that it’s too high in protein. (On the evening that I ate one of these bars, I measured my blood ketones at 2.4 mmol/L; when I measured the following morning it was down to 0.8 mmol/L and down to 0.3 later in the day. For me, on most days recently, my blood ketone levels are almost always above 1.0 and not infrequently above 2.0.)
Also, intrigued by the glycine discussion (and mention on two recent podcasts), I ordered some glycine and tested before and after taking it. (I didn’t see a change in my blood ketone level, but glucose was up slightly when measured by one meter and a lot when measured with another. That was just one test; I will continue to experiment.)
I’ve found, too, that consuming MCT oil creates a rather dramatic rise in blood ketones. I’ve done just one test with exogenous ketones and saw a more modest increase that didn’t last very long.
Over time, I expect that I’ll be testing a lot less frequently, but at the moment I’m doing a lot of self-experimentation as I’m curious about what various foods, supplements, and activities do to both my glucose and ketone levels.