“Over the hill” often means “past it” or some notion of being near the end. I prefer the meaning that says it’s when things get slightly easier, and achieving momentum in whatever you’re trying to do takes a bit less blind huffing and puffing.
The tricky bit is that you rarely get to see how much further you’ve got left to climb, and when the hill you’re encountering is a business or a big campaign to grow something, it can be tough motivating yourself with the idea that you’re nearly there when so far that’s not come true.
The answer is, of course, that you’ve got to keep pushing. If there’s genuine evidence you’re getting somewhere, and that what you’re doing is working, then keep the faith. If you’re getting steadily higher, keep going. No matter how far away the top is, you’ll eventually get there. So long as you don’t stop doing what’s keeping you going.
Sometimes, though, there’s a point when you need to give up. Some of the most robust of characters see this as par for the course of having ambitious plans. For others, though, it only happens when you look back after you’ve lost everything and you really are worse off than when you started.
Responsibility for taking this decision doesn’t just lie with you. Those of us watching with admiration at the determined and motivated around us have a duty sometimes to say when enough’s enough. If you know someone like this and can only talk about their determination, and never honestly say “they’ll get there – it’s such a great product / service – they just need time”, saying what you really think could be the best thing you ever do for them. Who knows – a small bit of honest feedback could be the breakthrough the very barrier to progress itself.