It doesn’t cost much more to have a silkscreen for captioning. On the silkscreen, indicate part identifiers (R1, C20, L2, D6, etc.). This will help you assemble components, especially when you use surface mount parts that have no IDs (such as small surface mount capacitors). You may not have enough space to specify the values, but that’s fine, since you can look it up from your schematic.
On the silkscreen, also draw the 2-D dimensions of parts. This will help you space out components for easier assembly and probing.
Last, but not least, use the silkscreen for reminders, such as the polarity of plugs, pin 1 of headers/chips and etc.