I imagine that this question has been discussed before ... however, a quick glance through the first few pages didn't reveal any specific discussion, so here goes ...
I have bought a number of collections with sets that are missing one or two stamps. Often these are commons that don't catalog very high ... an example might be a recent purchase that included several CTO sets from Laos 1984-85. Each set has 7 stamps plus a SS. I have 5 or 6 stamps in a dozen sets. Finding the SS by themselves isn't too hard .. but what's the best path for buying the individual missing stamps? I don't really want to buy complete sets (as that's probably how I ended up with the partials in the first place).
Will dealers want to fill my 'want list' for individual common stamps that will break their sets?
Will I end up paying full CV plus a premium if they do so? Seems silly to worry about that for $.25 stamp .. but if I need a lot of them ... well ...
are there other ways to fil those gaps? I tend to be OCD about my album pages ... I'm sure I'm not unique in that respect

thanks for any disucssion and/or advice.