Do I really need a guide for Shishapangma?
You will need help getting a permit and entering Tibet at a minimum. Once there, It all depends on your skills, money and time available. Shishapangma is a serious high-altitude climb. Some people go to Shishapangma without a formal guide and contract with local agencies for yaks, porters or carry everything themselves but this is probably not an option anymore. There are few climbers on Shishapangma so you would probably be alone much of the time. In harsh weather (white-outs) or in a medical emergency, you will be on your own so consider your skill level carefully. Climbing alone or in too small of a team is never a good idea.