The thickness of plywood for subflooring depends on several factors, including the spacing of the joists, the stiffness of the subflooring, and the type of flooring being installed. Here are some key points from the search results:

• The minimum thickness of plywood for subflooring is about 5/8 inch, while OSB must be at least 23/32 inch due to its weaker fastener-holding ability.
• For standard-width flooring joists spaced 16 inches apart or less, half-inch plywood is a solid choice for most homes.
• Some experts suggest that 15/32-inch plywood should be standard if the underlying floor joists are spaced 16 inches apart or less, but you should use slightly thicker 3/4-inch plywood for joists spaced further apart.
• Plywood subfloor sheets typically come in 4 by 8 or 4 by 12 feet in size.
• The optimal thickness of subflooring for insulation purposes is 15/32 inches for a plywood subfloor with joists spaced 16 inches apart or less.

Based on these sources, the recommended thickness of plywood for subflooring ranges from 1/2 inch to 3/4 inch, depending on the spacing of the joists. Its important to note that thicker plywood may be necessary for stability and support in high-traffic areas or for heavier flooring options.