Certain missions from the GDI and Nod campaigns allow you to carry over a percentage of the credits from previous missions. For Individual level runs this means you are able to start with a TON of money at the beginning. For example, I play GDI Mission 2, I let the money regrow and I save up 400k credits, I beat the mission and start mission 3 I will start with over 50k credits. This allows you to have more options during a run such as NOT building a Refinery all-together.

• In earlier missions there is no blossom tree so you can accidentally harvest all the tiberium. To fix this, move an infantry unit on top of a square to keep the field alive. Doing this on multiple squares will obviously make it regrow faster.
• Infantry only take damage when they enter a tiberium filled square, but not by just standing still. Blossom trees on the other hand will kill nearby infantry over time.
• Set the gamespeed to Max for better results
• If your silo's are full, keep building refineries but don't place them, just cancel them. This will keep your money while emptying your silos.

GDI Missions that benefit from this Mission 2, 3, 8, 9, 10, 11

NOD Missions that benefit from this Mission 3, 9, 12, 13

For example: I can save up over 400k credits in Nod missions 2,8,11 and 12 or GDI 1,2,7,8,9,10