As I recall, it's quite minimal (to the tune of a few dollars per day). Low enough that once, when faced with the possibility of having to pay for it, I wasn't too worried about it. The bigger concern though is with in/out fees (fees the moving company charges just for putting things in storage and taking them out), which can be significant (approx $800 each as I recall, ten years ago).
One of the things behind pushing for door-to-door moves years ago was to avoid LTS/SIT (and associated in/out fees) if possible. As was explained to me though (over ten years ago), if your HG&E have to go into LTS/SIT regardless, then, if you wanted it to remain in storage for whatever reason, all you had to pay was the additional storage fees. HOWEVER, if your HG&E could have been delivered to your new residence without going into storage and you wanted it to go into storage anyway, then you would have to pay for both the storage and the in/out fees. There are two possible scenarios:
1) Your HG&E arrives at new posting faster than you do: This is entirely possible on a long-distance move because a long-haul moving company can move your HG&E coast to coast in 2-3 days (using multiple drivers), but you still have 9-10 days to drive across. Therefore, your HG&E has to go into SIT. If you want to delay receiving it, you should only have to pay the extra days of storage.
2) Your HG&E arrives at the same time or after you do: This is the likely situation on a shorter move (e.g. Petawawa to Ottawa). In this scenario, as far as the CF is concerned, there is no reason the truck can't go door to door, so if you want your stuff to go into storage, you would have to pay all th associated costs (e.g. in/out fees as well as storage).
Keep in mind that what I am describing is the situation when the powers that be (i.e. DCBA and company) were much more reasonable. The same may not hold true today....
Proceed with caution.