It is best to look at it from the point of view of investment. ATM I have just a handful, so it takes about a week to get to 1 Cub (appx $3.5) ready to harvest. Instead, I choose to compound, which means it will take less time to farm 1 Cub over time as there is more to be staked.

For harvesting for personal use, maybe wait for it to get to $10 minimum. Depends on the individual. Over time, the price of Cub is likely to increase significantly, which means less impact from gas per transaction.