To centralize the tool string in large diameter tubing and casings.
Generally ran just above the pulling tool, but some applications may require multiple Centralizers higher in the toolstring.
After each use, inspect bow springs for cracks and wear.
The mandrels are much lighter than full size toolstring, so excessive jarring should be avoided.
Running through profile nipples will score the seal bore, thus damaging the nipple and plugs will not seal.