How do I know when I have enough information to act on simplifying an old or overly complicated investment portfolio?

For the long term plan, start by viewing all accounts as one portfolio. For the long term plan, identify the purpose, tax status, fees, asset class, and concentration of each holding, then compare the combined allocation with the household's goals and risk capacity. For this planning decision, a written target allocation can guide which positions to keep, consolidate, or gradually reduce.