Should I use glue or o-ring joints on a buried PVC waste pipe?
Typically, o-ring fittings are used for larger diameter pipes (4 inch and larger) where the runs consist of longer distances with a low density of fittings. Examples would be outside of the building civil work and inside (below grade) storm drainage.

When you have smaller diameter pipes and a high density of fittings, such as a bathroom group, glue fittings would be used.

Some advantages of o-ring fittings are:


fittings can be reused
quicker to install for large diameter pipes (> 6")
no time constraint for adjustment of fittings


Some advantages of glue fittings are:


fittings stay in the place they were set to
available for small diameter pipes
quicker to install when there is a high density of fittings