It depends on you really, if you are wasting 1000$ per day you will need a huge amount of bitcoins. You are using 10$ per day, ok you need in 100 times less bitcoins.
It may be that bitcoins do not hold any value after 20 years. Bitcoins are not a reliable currency currently and it has been here for very less time compared to other currencies but the future of bitcoin is not predictable. Soon it may be replaced by another currency.