First, my apologies though to the decent people on this newsgroup (and you know who you are)...
Answer #1: None you blankety-blank-stupid homeowner - they don't screw lightbulbs
-- they just screw customers...
Answer #2: TEN
1 to berate the customer about how dangerous it is to change a lightbulb since there is electricity inside the socket and he could burn down the house or maybe even the whole neighborhood 1 to tell the homeowner how unqualified he is to even attempt to do so 1 to brag about all the certification, training, and years of experience they have in light-bulb changing 1 to just berate the customer and curse at him for even asking a question 1 to assume that since the customer is asking a question, he must be "cheap" 1 to talk about how already by Wednesday night they have put in more than 40 hours of light-bulb changing so they don't have time to help anybody. 1 to tell the customer that he shouldn't even be asking any questions but should immediately call a repair tech anytime a light bulb burns out 1 to say that not only is a tech needed for changing a lightbulb but that legally homeowners should be calling a tech each time they decide to turn on and off the light bulb 1 to warn how no light-bulb changing technician would ever want to work for the diy'er since he is such a 1 to spout useless, irrelevant (and wrong) pseudo-technical misinformation about how to fix a doorbellSo you say but these 10 alt.hvac "pros" still haven't actually changed the lightbulb -- no problem. The homeowner just changes it himself since you really don't need an arrogant, trailer-trash alt.hvac tech to change a light bulb!