Dope and rests taken regularly can be a help (5)
I believe the answer is:
asset
'a help' is the definition.
(an asset can be a help)
'dope and rests taken regularly' is the wordplay.
'dope' becomes 'ass' (I've seen this in another clue).
'and' is a charade indicator (letters next to each other).
'taken regularly' means one should take alternating letters.
The alternating letters of 'rests' are 'et'.
'ass'+'et'='ASSET'
'can be' acts as a link.
(Other definitions for asset that I've seen before include "It's an advantage to declare" , "Valuable item" , "Tessa (anag)" , "Valuable thing" , "Valuable person" .)