In addition to the amount of money to be generated through each source, it is also essential to consider the timing of money coming through each source (see further details below on cash flow).
Yn ogystal â’r swm o arian sydd i'w gynhyrchu drwy bob ffynhonnell, mae hefyd yn hanfodol ystyried amseriad yr arian sy'n dod o bob ffynhonnell (gweler manylion pellach isod ar lif arian).