With your own design and scratch building, you're faced with questions not normally considered when building a stock kit.
For example:
Size of the model and power choice. Engine or motor?
How much detail will I need with my personal drawings/plans? The more detail the better, possibly. Extra work.
Do I cut this "Smoothie" wing in half and rejoin it for a small dihedral? Looks nicer. Extra work.
Ailerons? Pen lines to represent them or cut them out for a more interesting and scale look? Extra work.
Spring or shocked landing gear? Keeps the model from getting beat up a bit. Extra work.
1/8 or 3/32 gear wire? Weight trade off for strength? Not necessarily.
Removable wheels? Benefits. Extra work.
Wood selection? Totally your own decision. Give up strength for light? Maybe not. Use what wood you have? I like that.
Type of construction? Past building experience and the type of models you have experience building can determine this. Still have to pay attention to wood choice.
Fiberglass parts? Could work in areas depending on the model. May or may not save weight and could or could not offer benefits. Extra work.
Removable rudder and vertical stab? Makes shipping easier, smaller box if the model gets sold. Extra work.
Adjustable elevator or not? Small hatch. Extra work.
HDWE choice? Tom Morris. This one is easy.
Surface and finishing details. How far do you elect to take it? Boring, mild, excessive, or really knock um dead! Extra work.
Could be penalties for the latter.
For those that scratch build scale or semi-scale models,
What have I left out?