How do you integrate speed work into your regular running?

Hey all,

Since starting to integrate more trail running into my regular runs and typically aiming for at least 1 solid long run on a mountain (1000m / 3000ft elevation gain) weekly, I've found that if I still want to maintain high mileage weekly that I struggle to have days where I integrate speed work. I often feel like my legs/muscles are sore enough that my gut instinct is the risk of injury from the speed session is higher than the gain from doing it.

In addition I just find the trail and mountain runs much more enjoyable so don't feel compelled to downgrade my longer trail runs to add in speed sessions.

Curious how speed sessions factor in for others and how easy/manageable it is for you to add it in during especially higher trading periods either by volume or elevation.