In sequenced music, one of the ways we avoid a static, machine-like feel is to create a tempo map. Usually, this involves adding a few BPM to the choruses to create a little excitement. This follows our natural tendency to speed up when we come to a more exciting portion of the music (usually the chorus). However, not all forms of music benefit from tempo variations. An obvious example would be some dance-based styles, many of which require the metronomic pulse supplied by a fixed tempo.
That said, even with sequenced music written and performed only in a studio context, it can be worth adding a BPM or two to the chorus section to see what effect it might have. However, it is probably best to set up this tempo structure before any live audio is recorded (such as the vocals) — although if the variations are kept subtle (a few BPM), tools for time-stretching and compressing audio included with most DAW software ought to allow such change to be accommodated after the fact.