In SX Microcontrollers, SX/B Compiler and SX-Key Tool, George Herzog wrote:

One point of view is mentioned in Al Williams book [but actually about RS-232 interface, not resonators].
He points out that there are indeed a lot of things you can do when making a bench prototype that should best be avoided in actual production.  This might be one of those.

So when you make a board, provide for the resistor [you may omit it, but at least you can add it if you find trouble]. Gunther has gotten me concerned about the ambient temperatures which are quite high here.

Apparently, Murata came up with a better product by including the capacitors inside.  That may evolve into a procurement problem if you want a particular frequency.  So provide for the capacitors, too [when you decide what you are using, you can add or omit].

There are lots of schematics that will load up with components that no one ever really needs to add.  When you look in an actual product that is bought to market, part count can make or break profit.  So it is up to the engineer to determine the optimal design for the expected market and expected life of the product.

Finally, I do wonder about the power drain on the SX to drive a poorly configured resonator or crystal. After all, it does convert to heat.  I suspect that you could sequentially go through the FUSEs to get the lowest power drain without the add-ons.  Then you might add the resistor, etc. and see if you could get an even lower power drain.  Efficency is a useful design parameter too.

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