True, Snarkhunter. I always look for the shields under the heads. When I'm using them for big structures (like Great Wonders), the time to complete may not drop. Besides, if I'm using them in a metro, I like to use them to throw in extra shields, assuming my beakers and cash flow allow it. That way I (hopefully) won't lose a turn to pollution. I've had that happen a couple of times lately, where I've had a city producing exactly 100 net shields on something that costs a straight multiple of 100. Boom! I get hit with pollution, lose a turn, and wind up having to waste bunches of shields.