Standings have several uses depending on what you are doing.
If you are a trader, you want really great standings with the faction and corp running trade hubs to lower fees.
If you are an explorer traveling through low or hisec youll want to not have negative standings below -5 to avoid empire navies from chasing you.
If you want to run missions or epic arcs, youll need decent standings with either the faction to access all corp/agents or you can do certain corps. The standings has to do with what level agents you can access.
Locator agents require standings as well.
Low to zero reprocessing fees require standings with corp that owns station.
Sisters of eve arc (as well as all arcs) can be repeated every 90 days. The sisters arc can also give standings for each faction (but only one per run)
I was just giving a broad overall explanation of what standings are for.
As far as #2. Its good to have an idea where agents are at for the corp/level you are doing. You can decline the same agent once every 4 hours. Penalty for declining a second mission in the 4 hour window is a small standing loss to faction and a bigger standing loss with that agent and corp.
Running 16 missions for the same faction and same level will give you a storyline mission which will give you faction standings, but also give negative standings with another faction. (They can be declined without penalty).
SOE is about 1000 isk per lp which is considered small, Faction warfare LP ranges from 1000 to 1600 depending on times of the year, Thukker tribe is about 2000 blood is about 3500 serpentis is about 5000 ore is about 6000.
nah… High Sec mission L4… Trust Partners or other fraction BUT high sec. Got drake, it’s PancerDrake but slow like hell… got raven Fit but still not enaught skill for all parts of fit… sooo still L3 mission runner.