Using Ad-Block seems only fair when the ads are REALLY annoying and the site does not need the ads. There are e.g. sites where I safe 50% of my time using adblocker, as I
A.: don't have to click away the ads.
B: can see what I wanted without waiting for partly 10 minutes of ads before it
C: don't have to use my virus scanner because of the potential malware in suspicious ads (with faked x-buttons e.g.)
D. don't have to close up to 25 pop-up windows because of 1 site
However, many sites know how to place advertisement in a way that its not as annoying as this, and many sites really life by ads, so I have addblocker disabled on very many sites, but on sites I view for the first time or which have really horrible ads I won't disable them in general. (Btw, I'm not native english speaking and I'm tired, whoever sees my mistakes... please just overlook them, too lazy to correct them. You can understand me after all, and thats what counts here.)