Hi Casper, we’re all different so I suggest trying different styles and distances and see what feels comfortable. If it’s anything like me it may change over time. I started off doing mainly 5K’s and 10K’s and got down tot he low 19’s, and my first ever marathon was 3 hours 19 minutes but my hip felt terrible afterwards and led to a one year layoff with not being able to run more than a mile or so. I got back into half’s and 5K’s but over time the 5K’s hurt more than anything else, but I did break sub 19. Then in 2015 I read a couple of books about ultra marathons and decided I had to try one. Too my surprise I was good, very good at them, and they didn’t hurt my hip at all. I’ve gone on to run sub 20 hour 100 miles and won about a dozen ultras. I very rarely do any speed work in training and just leave it for actual races. I switched to a keto lifestyle to minimize inflammation and I think it’s helped me. Listen to your body and you’ll find your sweet spot. Hope that helps, Dave.