I am 49. Re wheat, volume and open interest should reflect the size the size of the underlying physical, in this case the size of the crop. For example, you risk running out of sellers should open interest increase to a point where it consumes a significant percentage of the crop. This has been the case in CBOT wheat where index funds are long 215,000 contracts. Ultimately, the futures and the cash become disconnected and the futures become meaningless, just a number. This also characterized by fewer commercials maintaining long positions. The lack of liquidity in some contracts(large spreads between bid and offer) can reflect an unsuccessful transition from open outcry to electronic trade. Typical of a contract with a smaller underlying physical. With open out cry (trading floor) you have locals who act as market makers and serve to narrow the bid-ask spread. Those same market makers are less likely to continue to trade in the same manner with electronic trade. Speaking for myself, there were times that I had positions in 15-20% of the open interest of a contract. With electronic trade I find that I don not have to carry such a large position to be successful. The large spread between bid and offer is often the characteristic of a contract in decline. Regards, local.