You'd be surprised how quickly it comes back. I recently had to design a simple ~50 node circuit after ~10 years of not doing anything of the sort, and I had it simulated in SPICE and prototyped after maybe 10 hours of work over a few days.
We had to learn SPICE in my ECE program. I found that inexplicable- writing a circuit in SPICE is like using a slide rule. I can derive a circuit on paper (just as I can do math), and I can use an actual circuit analyzer (just as I can use a calculator). Knowing the foundations of simulation programs is justifiable, but using and practicing with them is just excessive. As the circuits got more complex, I "cheated" by using a script to generate netlists and eventually I just used LTSPICE because christ, I have better things to do than type until my fingerprints wear smooth.
