[strela]

I use what I call the "Spot Rule" these days to let my body tell me when to take a break. If I start seeing little floating sparks or globes or a haze in the center of my field of vision, its time to rehydrate and get under some shade for a while. Then, the spots go away and I can continue. If I see them again, I call it a day.

[2Trievers]

I use the SAME rule here too ... but that's after drinking several ounces of Lagavulin! LOL *wink*