Electrical help please!

Hi folks, given that I know that you are all people of impeccable character and good taste (handsome too I wouldn't wonder), I was wondering if some clever people out there could answer a question for me:

What the dickens is killing my daylight bulbs? Both of mine have gone in the space of a week. Obviously, you're going to need a smidgeon more information than that so here goes: I use a pair of desk lamps to light my work space, in both I use energy saving daylight bulbs (this one:big lamp and this one:little lamp). The lamps themselves are rated for wattages far in excess of the 30W and 11W that the bulbs draw:

40W has small edison screw, 60W standard bayonette.

Now these bulbs are supposed to last for tens of thousands of hours. I'm replacing them after about four months. My usage is about 8 hours on a day, no switching on or off regularly. Have I miscalculated? Is the problem that the output of these bulbs is worth 150W and 60W respectively? I assumed it was all about the draw, not the output. Or is it just that four months is a realistic timeframe for modern (presumably less well made now they are mass market) energy savers?

Thoughts clever people? I've no intention of making this a debate between Camp Incandescent and Camp Energy Saver because frankly, especially in the EU, incandescents are dead. Like a lot of nineteenth century technologies. If it is the shades that are the problem I could probably remove them. Who knows? I'd like to!

I've got the replacements ordered from Energy Bulbs (who are ace and deliver very fast) so lost time isn't too much of a problem but I want to know if this is just a reality I should be budgeting for, a mistake in lamp choice (more annoying as it would be more expensive than a bulb ;) ) or something else? Thanks in advance.

Edit: I've had info that apparantly it is output and the heat generated that the lamps are rated for so that might be it. Righto! If anyone has more info, please share! Looks like I'll be using the replacement bulbs in these for a while until I can source more bulb friendly versions.

TTFN