I think if you're willing to cut your losses, now's the time to do it. ETH has been falling for a while now and will likely continue doing that. You can reinvest in smaller altcoins to profit though.

You can invest in other alt coins that have potentials in the future because you may not know for example if their project will succeed in the future, so you will succeed too. You can distribute your ethereum by investing some portion of it and holding others. We can never predict the value of ethereum so it is way more safer if you also keep some of your ethereum with you. Just like what I am doing right now, I have my ethereum and I also hold some of my alt coins. 

I think now is better to hold Ethereum because all alts are droping because of bitcoin drop. It will be better to hold it till btc will gonna be stable.

You should see the market trend that is the price of altcoin is increasing if yes than see for how many days it started to increase. If it is incresing more than a week than invest into it.

I think its better to find any alt with strong project and team but with low price like Stratis, Komodo and ARK because Ethereum price is too high now, I think it would be better to invest in some alts wiht low price.

You can hold some ETH and and buy some alts.
Get some cheap coins from the top 50-100. Look into them and see which ones you like and you think have potential for growth.

It depends on what one's goal is. If it is is a long term investment than it make sense to focus on one cryptocurrency, rather than investing in few. Having a focus is important as it is a very good idea to follow the news and to try to understand the market trends. The more alt's, the more time one needs to spend on them.

You can hold some eTH and and buy some alts. Get some cheap coins from the top 50-100. Look into them and see which ones you like and you think have potential for growth.

There are good alt you could buy i am not saying eth isn't a good buy but it has developed and increased a lot from ETH initial offering it is advisable to buy a new alt with distinctive potential than eth by so doing much profit.