Knowing when to drink caffeine and when to not can be tricky.The best time to drink caffeine, and probably the only time you should, in reality is when you legitimately need it.
This could vary on a daily basis and for the person drinking it.
For me personally, that means that I can't drink anything more than a soda or tea after around six in the evening if I plan on falling asleep easily or at a decent hour.
If it was a rough night and you have a long day ahead of you (like Mondays) then you could use a big ol' cup of joe or something with a little more kick like an espresso drink. Make sure to eat something though if you're prone to getting the shakes.
Coffee as your breakfast is probably not the best idea though. For one it isn't healthy and for two you'll most likely end up hangry once the coffee wears off. You're better off with granola and yogurt or oatmeal.
Go for the coffee/tea/espresso if you have a long day ahead of you filled with errands or work, but no time for a nap. A nap can be reviving, but that isn't always an option. Especially if you're busy.
Never, by any means, find yourself grabbing an energy drink.
They are completely awful for your heart, filled with crazy ingredients that I can't even pronounce, and you'll end up crashing. Hard.
Here's an article to dive a little deeper.
When to chug a coffee and when to not is solely up to you. You have preferences and understand your body and how it is effected by caffeine.
If you don't have that understanding yet, that's okay! Make yourself aware of what helps and what harms you and your anxiety will thank you!
