Eth will keep rising as more and more devlopers come on board. This is the uber coin the next big thing after bitcoin. If your not holding a decent amount you'll be kicking yourself after this baby hits 100 usd per coin.
I will quit my day job if ever ETH hits $100 and would be happy to retire at a very young age.
ETH has unlimited supply right? I mean it's supply is not capped as in bitcoin and each year we can see more ETH in supply. But if there are more Dapps coming on the ethereum blockchain, I guess the demand will still be high enough to keep the price rising. I think it is best to have some ETH in a well diversified portfolio.
Or you could just buy low and sell high and wait to repeat the entire process again and again as you get opportunities.