The best way to keep track of your cryptocurrency investments is by using a software called Blockfolio. It's free, it's easy to use, it's available for both Android and iOS, and it has a ton of features.
It allows you to set alerts for when the price of any given coin goes up or down. This means that if you want to know when Bitcoin hits $3k, you can set an alert for that price point, and then be notified whenever it does.
Blockfolio lets you track the total value of your portfolio in real time (as well as its individual coins). This makes it easy to see how much money is being added or lost at any given time, which is especially helpful when trying to decide whether or not it might be time to sell off some assets and take profits before they lose value again (or perhaps even go back up again).
It also lets you set up "watchlists" so that every time one of your favorite coins goes up in price by more than 10%, 20%, or whatever other percentage amount you choose.