When you think about 'reinvesting' with bitcoin mining you should calculate carefully that the yield after reinvesting will actually be more than the yield you were getting initially.
Because of the difficulty changes.
Just to be absolutely sure your principal stake is not actually slowly shrinking.
This gets confusing, at least for me.
Just pointing something out to you. Might be important.
Oh, hey, i make big mathematical errors sometimes, so try to double check anything i say before you act on any of it.
My understanding is that the date at which you invest is irrelevant, as the price drops in proportion to the increase in difficulty.
E.g. - 20% increase in difficulty, 20% decrease in price.
Due to this direct proportionality, i'm not certain that your ROI(%) should ever change? Except with a change in block payout?
I believe you missed the concept.
placing all of your return into the purchase of additional shares might not increase your return to its original amount.Because difficulty usually increases.
"20% increase in difficulty, 20% decrease in price."
True but did you forget something?
Your holdings at that time are not automatically increased by 20%!That would be nice, same payout/return forever. Unfortunately not.

I hope i can get the point across, i would hate to see anybody miss it.
i ran the math actually, but not very carefully. so im not sure which way it goes.
repeated iterations of simple formulae became tedious, so ive dug up an emulator for a good programmable scientific calculator.
[ti-86 the best i know] my second and last ti-86 became inoperable, and so of course i got rid of it,... along with the instruction manual lol

its been a few years so it's taking awhile to remember the correct syntax, etc.
No, i understand completely, im just saying that because the difficulty increases 20% and the price decreases, doesn't your ROI in terms of percentage remain constant? Assuming a constant GHS rate and block reward of course.
Also, what i believe matters most, is buying GHS at the nearest opportunity of a price drop after a difficult y increase.