When should I change up my workout?

[Spider Monk]

Good afternoon, all.  About just over a month ago I discovered NerdFitness.com.  I started reading into it and I loved it.  This site and everyone therein is a total match for me.  Fast forward about a week later and I started doing the Angry Bird Workout.  I love it!  I have leveled up in each exercise except the back exercise.  I’m still doing the inverted row but with a goal of 30 reps.  It's been a month now and I'm wondering if I should change up my workout or not.  I do the workout as a circuit every two to three days.  It goes like this:

 

Squats (level 2)

Push ups (level 3)

Back exercise (level 2a)

Planks (level 3)

 

If I do change it, I was thinking of doing this:

 

Lunges

Dips

Assisted pull ups

Crunches

 

If I do do this, I would not have the reps per level already figured out like the Angry Birds workout already has.  So my questions are these:

 

Should I change my workout?

 

And if I do, how can I come up with the appropriate repetitions per levels like in the Angry Birds workout?

 

Thank you all very much,

Spider Monk

[Dleffe]

I'd suggest alternating between both of those, with a day of rest in between.

[Tanuki]

Change it up by trying the harder version of the exercise. So, if you can, comfortably and with good form, do 3 sets of 12-15 pushups, try diamond pushups or decline pushups. Move from squats to split squats, planks to leg-lift planks

 

Start Bodyweight and Strength Unbound (google em) are great resources for reading up on the progressions through harder exercises.

[Evicious]

Here are a few articles you might be interested in to help you determine if you're ready change it up, and how to go about doing that:

 

How To Build Your Own Workout

 

Advanced Body Weight Workout