So much misinformation in this thread.
It's actually very, very easy to maintain above 90% of max strength on limited training once you actually achieve it. For example, I hit a 625lb deadlift weighing just a sandwich under 200lbs when I had abandoned playing tennis and was focused on nothing but strength.
I decided to get back into playing tennis a few times a week, started doing some interval running 2x a week, dropped my strength work to 2x a week with literally 4 movements only (Standing Overhead Press, Barbell Deadlift, Weighted Pullups, Ab Wheel) as opposed to the 4-5x a week before, got my weight down to the mid 180's, and was able to pull 550lb+ pretty well anytime I wanted to without thinking twice.
Fast forward a few more years to currently, I have dropped weight down to the mid 170's, am running about 40 miles per week (increasing to 50-55 gradually) to get ready for a sub-90min half, strength training 2x a week with nothing but kettlebell swings, pushups, and ab wheel work, and walked into a gym and pulled a 500lb deadlift without touching a barbell for almost two years. I'm pretty sure that with 4 weeks of barbell training to hammer out the technique and timing again, a 550lb pull would happen.
After you hit your strength goals, I would take the weight you hit for 10 reps and do something like 5 sets of 3 once or twice a week with a bit shorter rest and a focus on doing the lift as explosively as positive on the concentric while controlling the eccentric. You will more than maintain your strength if not get even more explosive and it will not be all that physically taxing.
Let's say my three big movements were Overhead Press, Deadlift, Weighted Pullup, and I hit 185x10 for Press, 405x10 for Deadlift, and BW+45lbs for Pullups, I would do something like this if I wanted to train 3x a week:
Mon: Press, 185 x 3 reps x 5 sets / Pullup, +45lbs x 3 reps x 5 sets
Wed: Deadlift, 405 x 3 reps x 5 sets / Ab Wheel Rollouts
Fri: Press, 185 x 3 reps x 5 sets / Pullup, +45lbs x 3 reps x 5 sets
Mon: Deadlift, 405 x 3 reps x 5 sets / Ab Wheel Rollouts
Wed: Press, 185 x 3 reps x 5 sets / Pullup, +45lbs x 3 reps x 5 sets
Fri: Deadlift, 405 x 3 reps x 5 sets / Ab Wheel Rollouts
Those sessions would not take very long at all and would allow time to add in some stretching, yoga, plyos, sprints, endurance work, etc. without being too much of a burden from both a time standpoint and a physical taxation (recovery) standpoint.