1/2 in. Swivel Seal Gasket

[DCB]

I’ve embarked on my first time effort to replace faucets in bathroom and kitchen. I’m wondering whether you more experienced RV plumbers have found it necessary/helpful to have a supply of washers/gaskets on hand for the 1/2” swivel connections throughout the rig, like the one shown in the 1st pic below.

Is the 2nd pictured item the appropriate part? Have you found a reasonable supplier? Thanks for any words of wisdom!