What is dissolve delay?
The dissolve delay is a setting on your neuron that determines the minimum amount of time that you have to wait before you can unlock your original locked ICP utility tokens. This is a separate function to the time you set to stake or lock up your ICP. When you use the "Start Dissolving" command, your dissolve delay will start decreasing with the passage of time. You cannot remove your ICP from a locked neuron until after it has completely dissolved and the delay time has hit 0.
The length of the dissolve delay can enhance your voting power, and therefore, your voting rewards. The higher the dissolve delay, the higher the reward. The maximum dissolve delay is eight years. If the dissolve delay is below six months, you won't be able to vote. While the neuron is dissolving, the age bonus is zero. You can pause or increase dissolving whenever you want.
If you would like to calculate your neuron's rewards based on your dissolve delay, check out this calculator: