Ah, the obligatory "get to know you" post. Well, without belaboring the point too much, I am a runner. I'm an established marathoner. At the time of this writing, I've done 10 marathons. I exist on the periphery of the so called "ultra community" (ultra running is when you run races longer than a marathon). By this I mean that I'm not regularly running at this distance like marathons (yet!), but I have done a 50km and a 50 miler. On top of that, I've done an exotic race called the Triple Crown where you race a half marathon, followed by a 10km, followed by a 5km all back-to-back. I can't even begin to count how many 5km, 10km, 15km, 2 mile, 5 mile, 10 mile (essentially any popular distance under half marathon) that I've done. For a while I was racing on average around 2-3 times per week, sometimes 3 to 4 races on the same day and 6 in a weekend! I've even done a marathon in the morning and a 5km that afternoon.
I must point out that I'm in no way qualified to give out any advice on the topic of running. I'm not a certified trainer of any kind or coach or anything like that. I do feel I have some things to share from my own training that others might want to consider. The advice out there can be just plain bad and counter productive or conflicting. These are going to be my thoughts and what has worked for me, personally. Not everything that works for one person works for everyone. In addition to the resume given above, I've never been injured (crosses fingers), which is something important to consider when taking advice from someone. Sure, some coach might be able to get you a new PR on your 5km, but are you going to end up with a busted knee like him in the process?
Speaking of breaking records, I should mention that I'm not fast. You can see my PRs, and you can realize that I'm probably faster than average, but I am FAR behind the leaders of the pack on even small local races. I just don't care that much about it. I enjoy running, and I run for fun. If I stop finding it to be entertaining, I'll simply stop running. There are plenty of other things to do with my time. And with that, I'll end with my first advice: if you don't enjoy running, don't run. Do what you enjoy.