Caffeine affects everyone’s body differently. Some of us can knock out after two cups of coffee whilst others end up pulling all-nighters after half a cup.
It’s all about discovering how your body reacts. If you’re having no trouble sleeping, you’re good to go. Trouble sleeping? You need to reconsider your caffeine intake. How much and at what time are you drinking caffeine?
Remember, caffeine can stay in your bloodstream for up to 6 hours hence why you should not consume caffeine during the evening.
Caffeine found in coffee has a more potent effect on your body and it's biochemistry, than that of caffeine found in tea, as they are slightly different chemically.
Try a herbal tea in the evening or just before you head to bed, like camomile, which is known for it's relaxing effects.