now I starting doing signature campaign, if it is last until 20yrs. I got my bitcoin for almost 50BTC in 20yrs. calculation for this 2.5btc per year doing signature campaign multiplying the year, 20 years you got 50BTC for retirement.
You might get 5 bitcoin each year now, the amount you will get will halve every year due to bitcoin price rise. You will get about 10 in total.
I think that's a good range of collecting bitcoin for 20 years , so in total you are able to get 100 bitcoins after 20 years.
And I would say that is already enough for your retirement in 20 years. And it is better if the price of bitcoin by that time is already $10,000