Best Flowering Results

Is it better to cut off fan leaves and other extra leaves so it saves the energy for the buds and light can get down to the bottom of the plant?

Ask yourself this, will a plant that uses energy made by the leaves grow better with or without said leaves? Nope. Some minor trimming if using low powered lighting, or moving of the leaves, then sure, but avoid trimming when all possible.

IMHO
Trimming is all dependent to the system of growing you are doing aswell as the genetics you are using. For instance, In a SOG and other high plant density systems, trimming is employed to increase light penetration so buds can form lower down and to keep the plant healthy through efficient ventilation. This may be necessary to a greater or lesser degree dependent on the strain grown. Failure to do this with some strains can lead to poor bud development, bud rot, and the easy transmission of pests.

Again IMHO,

It is unclear how much energy obtained by the plant through the fan leaves specifically is used in flower production. Sure, Its self evident that during the vegetative phase the fan leaves powers the development of roots and stems, however I (like others) suspect these fan leaves to be of lesser importance during the later flowering stage. Anecdotal evidence has shown many grows on these forums where trimming has shown to have little or no negative effects on the size of buds. I grow a few different strains side by side and seriously need to trim some strains because they have a ridiculous amount of fans, (Greenhouse Exodus being one).

Im interested in other opinons though.

If they are green and healthy I keep them. I only pull yellowing or weak leaves regardless of how many of them there are. Like monkey floss said it is and probably should be done in high plant density setups (lollipopping) but otherwise you need to solve the problem during veg with lst, topping, supercropping or a combination. That is my opinion.

I used to cut a few selected leaves. Now I just move them out of the way. I haven't noticed any real differences... But I figure I might as well keep as much of the plant in tact as I can. Plenty of leaves will yellow as time passes. Those are fine to pluck off.

just a seperate side note, the fan leaves often yellow during flowering and wither and fall off anyway, its sort of the plant feeding on itself, happens excessively during a flush, if you choose to go that way or not. but i imagine theres a balance somewhere between leaf number and rate of turning light into energy etc

if you are going to trim you should do it before you go into 12/12, after this point i'd leave em, last thing you wanna do is shock and stunt her