I am an AFOL and just getting my collection of Legos built up again. Who knew when I was 20 something that I would still be wanting to build in my 50`s. I am asking for advice. I have purchased some creative boxes and the architecture studio. I am finding that even though I seem to have many pieces, I don`t have the right ones to finish a build. How does one go about growing their Lego supply so that it includes needed pieces? Thanks for any assistance.