If someone wants to invest in ALTs then he must pick top 10 to 15 alts listed on CMC and study them for investment. Right now there are around 10k crypto listed on CMC and not all of them are worthy for investment. Bitcoin must be the primary coin where majority of your funds should be going and spend only spend cash into alts or in other words as much as you can afford to lose. Don't go for alts that look attractive due to cheap price, think wisely before picking your alt.
Even when you have a portfolio better 80% BTC and 20% can be for altcoins to avoid greater risk, indeed choosing the top 10 TOP altcoins on Coinmarketcap will be better than the basic order it is still uncertain and I said it would have a big risk.
Sometimes there are still many people investing in altcoins at low prices, seeing a low marketcap hoping that the altcoin can rise to x5 - x10 this is something that is not certain even when buying altcoins without in-depth calculations it will still lose at least he lost.