Support is there from time to time (3)
I believe the answer is:
tee
'support' is the definition.
(tee is a kind of support)
'there from time to time' is the wordplay.
'from time to time' indicates alternate letters (letters removed on a regular basis).
The alternate letters of 'there' are 'TEE'.
'is' is the link.
(Other definitions for tee that I've seen before include "Where one drives from" , "supporter on course" , "Part of course" , "Mark" , "Golfing equipment" .)