The cost of adding a feature isn't just the time it takes to code it. The cost also includes the addition of an obstacle to future expansion. The trick is to pick the features that don't fight each other.
“And for myself, I think for the present He is calling me to another land; but how long shall be my abode, or what employment He has for me there, I know not, for I cannot think He is taking me there to live and lurk only.”