Like I have said many times...Im lazy. But I'll spend half an hour, an hour or a day extra f I know its going to save me time in the long run down the road.
I use clay as a bed. There are different types and hardness. I just use a simple medium clay. It needs to be worked. The warmer it is the easier it is to manipulate. But its still a pain in the ass. So I try to save them if I can. If they haven't been coated once too many times, then I'll re use them as its less time consuming than starting from ground zero. But eventually the clay gets too covered in sealant and mold release it needs to be thrown out.
The use of LEGO means I can remake the frame to the exact same dimensions. MEGA BLOCKS (not recommended) deteriorate and never put LEGO through the dishwasher.