Erections get worse over time.
As we get older, erection quality drops. We aren't always full of energy, so we may need more time to get aroused, and more reasons to feel aroused. Sometimes — and it's okay — we fail at it. Nature decided that we need physical strength at the beginning of the life journey to reproduce; and as we mature, while strength may decline, experience and wisdom increase. But still, you'll be happy to know that many causes of erectile dysfunction are reversible, no matter how old (or young) you are.

Sometimes, erectile dysfunction is triggered by prostate health issues.
Treatment requires a very specialized medical approach that your doctor will discuss with you. Other times, ED is due to poor blood flow. Genital arteries become less flexible and so don't expand as quickly to let blood easily course through your penis. Fortunately, this issue can be fixed with medication that interferes with the chemical process allowing blood to leave the penis. (If blood sticks around longer, so does the penis.)

However, the most common root cause of ED is psychological.
Yes, that's right. We've all been there. We're too excited about the new partner, or we're too tired of the old one and, once faced with ED, sometimes we just lose confidence. Or, we get drained at work, we lose desire, we have no energy and... the worst bit, we're too scared to try. Every single episode of ED is a massive kick in the gut. But guess what? The key is to relax. Just relax... Sound like nonsense? Listen, no matter what's causing the issue (and we're about to get to the root cause in a minute), when you start getting all in your head, the erection doesn't get better. The truth is, it gets worse! I know it doesn't sound like the easiest thing to do, but during sex, you really need to stop thinking about the problem. There are so many things to focus on: the foreplay, your partner's pleasure, and the enjoyment of the whole process!
And the last tip: You definitely should aim for a full night's sleep, good work-life balance, healthy nutrition, and moderate physical activity. Why? Because they all raise testosterone levels, making your erections stronger and longer.