I pretty much never put down less than 140w if I get stuck on the front, but I won't do much more. That's the pace I can do all day long, and it's not going to fatigue me in the slightest. The other night, I led the final 4 laps of the crit...in the yellow jersey. I was basically doing 150-160w for those laps. If someone wanted to come around, they could. But I didn't care 'pulling' them around at that level of effort. It didn't affect my chances to win (and I did win).