Number of years should be a prior which should be considered as a target of accumulating. When you don have a specific period/duration or time horizon then surely such person don't have focus. And investor always have a time frame of investment and schedule himself of how to apply the investment strategy to meet up his target with the specific period of time maybe 4-10years intervals or 10-20 year. Surely there are times along the line of investment process when a person may be jobless or out of fund or discretion to continue his investment procedure and such person investment approach may slow down a bit but h/she will still have that focus and zeal of meeting up the target of that period of time h/she planed. Sometimes an additional year may be added if such person was financially unstable for 1 year or more. maybe the speculated time frame was 4-10 years minimum but may be extended to 4-11 years adding 1 extra year. So all implies that time frame is very important in accumulation process because it keeps you motivated.