I’ll start with a short, simple explanation of some basics for readers that aren’t clued up on keeping bees.
If we begin with the general type of bee hive that has been used by most keepers in France and the UK for the last 100 years or so which comprises a Brood box or what we could call the “hive proper” where the colony lives and the Supers which are placed on top of the Brood box for the excess honey production that the keeper takes. A Queen excluder is placed between the Brood box and the supers. This is a grill made either from metal or plastic that allows the workers to pass through but prevents the larger Queen from "getting upstairs" and laying eggs in the honey supers, however skinny Queens do sometimes get through.
Click to enlarge images.
If you look at the picture you can see these have wooden frames placed inside them, one size for the Brood box and another size for the Supers. These frames are to support the comb and it has been common practice for the last 150 years or so to pre fit these frames with a sheet of moulded wax to give the bees something to build on. The wax sheets are pressed with a honeycomb design and the size or number of these to any given area will determine or dictate to the bees the dimensions that they will use to construct their cells.
Frame with standard wax foundation fitted.
When we take and examine a piece of bee comb from a feral colony it soon becomes clear that different bee colonies make different size cells and more to the point the size of their cells varies in a single colony which would indicate that pushing bees down a one size fits all route may not be desirable, or more precisely may be desirable for the keeper but not necessarily for the bees. Of course we can’t know “if the bees care or not” but as I’m committed to leaving them to their own devices wherever I can I only use wax foundation sheets in the honey supers where the increased rigidity is required to withstand the forces from centrifugal extraction, (spinning). For the brood box frames I simply fix a starter strip of wax in the top of the frame to point them in the right direction, this can be moulded or plain, the rest is up to them. The important thing is to take great care in getting the hive level in all directions as the bees comb will always be vertical and we want the comb they make to remain inside the frames and integrate the stainless steel wires.
Frames with starter strips.
Natural comb drawn from starter strip.
Warré frame part drawn with natural comb.
Other than saving money another potential benefit for the bees maybe a reduction in any pesticide or other toxic build up there could be in using old wax that has been recycled from other hives. It won't prevent the bees bringing "cides" in but it gives them a clean start.