I had my first speed work session this week after months of not doing any, and I have to admit it was MARVELOUS! I did some warm up, some mileage, and then got to do some fartlek work for 20 minutes before I had a cool down. If you don't do speed work, you need to, and fartleks are a fun way to incorporate some speed work in your schedule. Most fartleks are short, with some recovery period (this time i did one minute at my 10 K pace and one minute of slow jogging recovery). To me, I can do anything for a minute or two as long as I have some sort of walk or slow recovery after that one minute.
I had another day of long running this week, again the same plan only this time we did three sets of 8 minute walks/2 minute runs and then 30 minutes of running. Makes my legs so much more happy to get to do the continuous running at the end versus the beginning.