Wood Clarinet Oiling
Clarinet manufacturers use oils basically in wood to prevent it from absorbing water, as water would cause issues for wood. Water is more susceptible to environmental changes. If wood contained water then if it was left outside in a car while the weather was below freezing the water would freeze & expand and split the wood. This is why we do not want to introduce water to a clarinet. Also check the sections on why Clarinets crack in relation to the temperature of the inside bore temperature versus the outside surface temperature.
I do not have a specific schedule of timeframes to oil a clarinet, but I use certain identifiers of when I should further check and oil a clarinet.
I normally check a clarinets top socket of the barrel as an indicator. If the socket looks dry and lighter in color than other sockets then you know that that section needs some bore oil. The top socket gets the most abuse as the mouthpiece shank may not be long enough to butt up against the socket base. This allows moisture buildup and thus more “wear” from playing than normal, this is why you should dry out your clarinet after every use.
As you move down the instrument the “wear” decreases in it’s quick impact. For instance, you may oil a bell once for every 15 times you oil a barrel.
If you put your pinky into the barrel bore and it is rough, then I use that as an indicator for bore oil there too.
You can use the same method for the rest of the clarinet of visual and feeling indicators.
But keep in mind oiling a bore many see as not needed, etc. Though many will tout its benefits. As other will tout the benefits of particular type of oils. As an example Selmer Paris puts the bodies into pressurized tanks for applying (linseed ) oil into the wood.
But the question of “how often” is superceded by learning to identify when it needs it as climate/weather, how often you play etc may dictate exactly when those periods are.
Of course, some clarinets bores are better finished than others, and being “rough” may be the norm. you have to be able to identify “rough” versus “that was the way it was reamed”. Which becomes easier once you know how to identify reaming marks – unless they were polished out. I think the point here is that you get used to it after doing it awhile and paying close attention to your instrument.
But before you go gung-ho on oiling be aware that any older clarinet may need to be cleaned out first. I basically use a 1/2 bristle brush (and other sizes) to clean out the bore and toneholes before I apply any oil. And I may use other minor cleaning solutions to get rid of various debris in the bore/toneholes.