Beer crate regularly dropped on your toes (5)
I believe the answer is:
alert
'on your toes' is the definition.
(I've seen this in another clue)
'beer crate regularly dropped' is the wordplay.
'beer' becomes 'ale' (type of beer).
'regularly dropped' indicates alternate letters (letters dropped at regular intervals).
The alternate letters of 'crate' are 'rt'.
'ale'+'rt'='ALERT'
(Other definitions for alert that I've seen before include "Watchful and bright" , "Lively" , "On one's toes" , "alarm" , "Watchful; warning" .)