if you're racing 10k to half marathon your work load/work out doesn't need to exceed 8k, that's true, however it all depends on what you're doing.
My best half marathon came right after a long track season where I did mostly interval work, hills and lots of tempos.
as far as the tired legs go, I think that your workouts are as important as your milage especially for 10k/HM. I wouldn't be doing so much milage that my work outs suffer.
that said, I like to cycle in high weeks where they fit. say I don't have a race for 3-4 weeks, I put in a couple weeks where I'm a milage whore, and I'll keep the work outs manageable through this time. by this i mean a bit slower and a bit more volume such as the 4x2mile work out at half pace. Maybe do a few more fartlek runs, these are nice when you're running tired (on purpose) because they allow you to get in a good hard effort but you don't have to worry about splits, and having a "good work out"
Ok I know this is getting a bit longwinded here, but I was talking to my old coach about this a few weeks ago and he was saying some people like to do cycles of 2-3 weeks at a time on a certain kinda work out, but he liked to give us a mix of stimuli each week. so we would run a thresh hold work out, and then we'd do a speed work out.
our most devastating month of training he had us doing 4-5 harder days a week, including the race, but that's not sustainable. so most of the time we would be getting in 3-4 hard days.
here is how I set up an ideal week of work outs.
m-10 mile steady state run say you can race a 55 run a 61-62 minute 10miler
t-ladder work out 3x4 800 mile 800 3x4 maybe at 5k pace
w-easy 8
t-light fast work out 4x400 4x200
f-easy 5
s-race
s-easy 13
only 61 miles, maybe not quite enough for you, but like I mentioned I think quality is important when training for 10k. I've had seasons where I tried to add in doubles a few days a week to get in another 10-15 miles but I dont think the added milage helped at that point. As I mentioned earlier there's a time and place for worrying about milage, and you're racing season is not the time for it.
notice we are working different systems with each work out, and the thursday work out is just enough to get your legs moving nice and fast, but not quite enough to tire you out.
the key is that you have to remember you have a workout on tuesday when you're doing mondays steady state run