Fact or fiction, mixing grease types

[sidetrack]

I have heard some say that you cannot mix grease either type or brand ? My bike comes with grease nipples on the rear shock linkage, after my last ride and wash I decided to pump some new grease in there. Obviously I do not know what type was used before. I cranked the grease gun until the grease pushed itself out by the pivot points. Should one strip and clean then insert and stick to a single brand or is it ok just to add grease as needed ?

 

[SabreF86]

 

[Hagar]

 

[Welsh]

 

[sidetrack]

 

[lecap]

 

[sidetrack]

 

[Pete HK]

 

[Bill the Bong]

 

[Piston Pete]