As a forklift instructor, my advice to novice operators when they ask should they use their mirrors when reversing, is not to rely on your mirrors because one day they be removed.

Novice drivers quickly develop habits and I usually twist the mirrors or remove them during training to encourage them to turn in the seat and look in the direction of travel.

One problem operators can have - especially larger ones - is actually turning their bodies due to the restrictive nature of modern forklift seats.

The only time I would sanction use of the mirrors is when destacking a very awkward load from height where the operators primary focus has to be on the load.