1. Do you only work with spirits if you only have a certain thing you want to maifest?
not sure of your question. do you mean asking a spirit for help only if you want to bring luck/love/wealth into your life? no, you can work with spirits just to talk. spirits are everywhere, some just travel around, others stay in one place, you could ask them for help with things, or you could just say hi.
2. when working with a spirit is it always a temporarily process and not a full time devoted thing?
again, depends, i've spoken to spirits on Samhain who were just passing through and i invited to stay for the night, and i've had other spirits i've known for years, it depends on the spirit really.
3. If you are working with a spirit for only a short time are you suppose to get to know it better before asking for help?
would be nice. most spirits were human once, so how would you feel if some stranger came up to you and get 'i was cash, can you give me money?' some you can ask for help in spells, but if it's the same spirit every time, ask it what it's name is or what it would like to be called, if there's any particular offerings it likes. stuff like that.
4. If you need help fast from a spirit for something dire, do you have to get to know the spirit?
well i've never really used a spirit in spell casting, but i have asked spirits i've lived with for years to help now and then. i think you're confusing deities and spirits, but in both cases if it's something dire they should understand and help you. for random things you might want to introduce yourself and ask if they're willing to help. [spirits and deities]
5. When working with a spirit temporarily do you build an altar for them and then take it down when the working is done?
it's nice to have a space for them to leave offerings as well as a space to call their own. you could simply have an altar for spirits and not a specific one. [some people keep an altar to their ancestors or to a departed loved one]
6. Can you stay devoted to a spirit and venerate them?
yes, but they're not gods, and the spirit does have limits as to what it can do. also some spirits are more powerful than others. [most orbs i've come across are the spirits of animals for example they don't have enough spiritual energy to manifest or take on a larger form] on top of that, spirits can cross over, sometimes without much warning, there's been a few times i've come home to discover a spirit i saw earlier that day was gone. sometimes they say goodbye, other times it's sudden, or they grew to weak to communicate.
7. Can you venerate more than one spirit?
well again you might be confusing spirits and deities but yes. as with gods you can work with more than one. in that case just make sure to devote enough time to each relationship.
8. If you dont want to venerate a spirit no more what should you do?
if you don't want to be friends with someone anymore what do you do? the mature thing is to tell them, calmly explain yourself, wish them the best, and to take care. usually they'll understand. however, with spirits [and deities] you shouldn't rush into things. work with them for some time before decided to work exclusively with them. this is a good way to prevent hoping from one to another once you get bored and upsetting a spiritual being resulting in your spiritual butt being kicked to learn a lesson. always be respectful. best way to prevent problems down the road.