Dynamic vs Static Resources :

SR means the resource is applied only once (the 1st time it’s needed).

DR means the resource is reapplied every time it changes.

The main difference between DR and SR is that any subsequent updates to the resource are reflected only to those elements that use DR.

SR and DR have different performance characteristics. DR requires more overhead than SR because of the extra overhead of tracking, while DR can potentially improve load time because SR are always loaded when the Window or Page loads, whereas the DR reference is only loaded when it’s actually used.

DR can also only set dependency properties whereas SR can be used almost anywhere