Different people and cultures believe different things for the answer to this question. The meaning of life as we perceive it is derived from philosophical and religious contemplation of, and scientific inquiries about existence, social ties, consciousness, and happiness.
A long-term financial plan should include these elements. Time Horizon. A plan should look at least  five to ten years into the future. Scope. A plan should consider all appropriated funds, but especially those funds that are used to account for the issues of top concern to elected officials and the community. Frequency.
Generally speaking, hang onto bills and bank statements for at least two years, and insurance documents as long as they are valid. When it comes to tax-related paperwork like pay slips, P45s and so on, HMRC suggests keeping them for at least 22 months from the end of the tax year they relate to.