It really all depends on what you're comfortable potentially gaining or losing. No one has a crystal ball (damn...if I did I would have bought a lot more than 15 ETH back in October when it was $10 a pop. Sigh)

I've learned the hard way DO NOT SELL DURING A "CRASH" - and another tip, don't buy high - when everyone is talking about how 'hot' a coin or a stock is, when everyone is involved, it's too late. Wait, and pick that coin up on a discount when it falls.

I think ETH is in for a bumpy ride. Luckily, I never put in more than I can afford to lose - and I was able to lock in profits from buying when ETH was $10 (DAMN I WISH I'd BOUGHT MORE lol) but even with coins I've 'lost' on - it's never lost til you sell it (or it goes to $0. Then, yes, it's lost).

Just look at BTC over the years.

Longterm - lots of kinks need to be ironed out with ETH...but I'm definitely not selling. :-)