Constructible parts are an important aspect of Restaurant Story. Without them you cannot build any of the appliances included in the goal updates, and thus cannot complete the goals to unlock some exclusive decorations.
As a result a lot of players ('parts players' if you will) like to accumulate a stock of parts via gifting for when the goals roll around so that they are in the best position possible to get the goals done in a reasonable amount of time.
But with 48 parts currently available to gift, which ones are the best bets? I've answered this question twice before, but that's the magic of the game - things are always evolving and changing - so there's no guarantee that conclusions drawn many months ago are still accurate.
So now we shall delve into the archives and observe any changes to the general trend of parts required for constructing new appliances. Since the
last such analysis took into account appliances added between October 2013 and April 2014, it makes sense for me to count all the cookers introduced in the time since.