Use them sparingly and when you want to either exagerate realtionships or fit in a wide angle of view. The wide angle is not a universal solution. Look thru the notes of many famous landscape photographers and it becomes obvious. It can be a bit of an easy route to achieving 'drama' and I for one am using them less than I used to. In 35mm terms, I use a 28 a lot a 35 quite a bit and the lenses up from that a little less when doing landscapes. I rarely need anything wide but occassionally do...sometimes a lot wider. A 28 however serves the majority of my wide angle needs with amoderate wide the 35 coming close behind. I suppose it depends on what you consider to be wide! I have some 21mm equiv lenses but have never really gone wider hn that.