I used to sweep up as much as I could in my woodshop and then finish with the shop vac. Vac bags were expensive, IMHO, and using it w/o a bag, even with the deflector installed, the saw dust and sanding dust soon plugged the filter. I tried cutting the end of the bag, dumping it and taping it back together. Worked once. The second time the bag apparently plugged for it certainly burst and the filters were plugged. I bought a separator for a shop vac since I liked the one used in the dust collection system. The shop vac is connected to it and the hose for sweeping is hooked to the separator. I think it works real good.
This was purchased from Rockler.com for $70 bucks, lists for $80 but is often on sale. They say it fits any shop vac with 2 1/4 in outlet but it didn't fit mine. It comes with a 4 ft hose to hook together but I wound up using the vacs hose and bought another. Lets me go a long way though. Holds five gallons in a 10 gallon seperator and you can see how much is in it since it is translucent. This could be made easier but you can tell when it reaches the full mark. Vern