Gotta build within your capabilities and budget. Also you need to make sure you have the basics down pat. In most cases lots of aftermarket parts won't help bad paint or ejection pin marks and mold lines. I build a fair number if out of the box to play with various paint techniques. I also build using some artermarket to develop the skills for the all out builds. However there is an lots that you can do without using a lot of aftermarket parts by doing some sdratchbuilding and re purposing various items for detailing.