skill modifying weapons drop from vAS, solo arenas (vMA & vVH) and 4-person arenas (vDSA & vBRP).
Use these staves whenever you are using a set that can be 1-barred, so you have a free bar for a special weapon. Check out the possible combinations in #combining-sets.
Don’t build specifically for these staves, but instead use it as a nice bonus when you have a free slot. The only “mandatory” staff is the Blackrose Restoration Staff in certain scenario’s. Link: combining-sets
dps-oriented options (vMA bow/vDSA bow/vMA 2h/vBRP dw/vAS dw) fall under a similar category as the vMA destro staff: ’no group support, but a small damage boost.'