[R] updating one's own package

[Wet Bell Diver]

Win7 x64, R2.14.1

Dear list,

I would like to get into the habbit of creating a package for each 
project. That way I can package my project-specific functions and data 
together and load or unload that at will. Also, it will allow easy 
navigation through all the functions I will have available for each 
project, since I can then use ?myfunction and immediately see the 
details of that function (esp. useful when revisiting a project after 
several months).
Anyway, I have been successful in constructing a package, using the 
package.skeleton. My question is how to easily update the package when I 
write an additional function or rewrite an existing function. Do I then 
need to again build the package fully, or is there an "incremental 
update" option somewhere? This I can not find anywhere, maybe I am 
overlooking something?

Thanks,
Peter