I only see the problem the last few months where they've been putting out a few fairly big releases, like the DEX210. I had to wait for... about 4 months to get an original DEX210 wing because I drilled the wrong holes first time around (small problem I know, but it was pretty annoying nonetheless).
However, if it's in stock online, I don't see the problem. Stock the most important spares and the comsumables at home and make sure you know an (online) store where to get other spares when you think you might need them. With any car I'm driving I've always had trouble getting spares from the LHS, so nowadays I pretty much order online only: UK if I need things quickly, US for SC truck stuff
and HK for cheapness and if the orders can take a little longer to arrive...