Where fades earn their keep
Killing clicks: any clip cut from a longer file starts and ends mid-waveform, and that discontinuity is an audible click - 0.1-0.5 s of fade removes it, which is why the ringtone maker ships with fades on by default. Song endings: the classic radio fade-out is 5-10 seconds of equal-power curve starting past the last chorus - cut the tail first in the MP3 cutter, then fade here. Podcast beds: 3-5 seconds out under the closing words; check the final loudness against your platform target with the audio analyzer or level it with the volume normalizer.