One thing we always take record at time of maturity (lasted period of investment) we might think we are over investing due to how other needs that surrounds us at the initial stage of investment might think we can't manage the situation at hand, what I also understand during investment is that we may finds it very difficult to increase our investment plan just as you said either by weekly or monthly but it should be in a way that we don't over stressed ourselves knowing too well that we can't go above our capacity or income we received. Maybe thinking how I wish their works allows them to earn higher they would have increased their investment plan maybe to make huge return or to increase profits before their expected date of harvest.