Ok my idea / can be adapted or refined a bit.
I think everyone needs work on their core and abs.
And this would serve to work at home - no equipment needed.
"Crunch Month"
Do each of these once a week, say generally 3 sets of 15. Add more reps as needed, as the month progresses.
Floor Crunch (3 sets of 20)
Horizontal leg raise (3 sets of 15-20)
Hover/plank (till failure? Or 3 mins)
Air bike (3 sets of 15-20)
Floor toe reach (3 sets of 15)
Side plank (45 seconds)
Tripod hover/plank (3 mins)
Can do these alongside your current workouts (so it doesn't have to be daily, as long as you get them all in each week), or do 1 a day and cycle them through. I listed 7 specifically for this reason.
Feel free to do extra as well, you might aim to do them all twice a week, depending on your current level.
Gives some flexibility and no need for this "catching up" business?