Hi Denise! I try to give each and every workout that I create a new and refreshing feeling. I do this specifically so that you can use them as new rotations. While I may repeat some exercises on the new tapes, I have added new exercises and combined the new and the old in different ways. I have also added a wide variety of rep styles. The tapes were designed as maintenance in the sense that you do not hit one muscle group for a very long time or use the heaviest weight possible. So, generally speaking, if you are currently at a certain strength point, you could probably maintain that strength point with these tapes for about 6 weeks. After that, I would suggest going back to PS tapes and push harder to get further strength gains. Guess what? If/when you do this, you will most likely find that you can actually lift more weight with the PS tapes after returning to them. That is because you gave your muscles a long rest in one department(focused strength) and utilized them in a different way with the 6 pack(muscular endurance). Hope this helps!
As a side note in case anyone is wondering, it is important for me to point out that while I have mentioned that the 6 pack tapes are good for maintenance, it truly will vary per individual. Example: If you are new to lifting weights and suddenly use the weight sections of the new 6 pack series to get fit, you are definitely going to develop a signifigant amount of strength gains, while somebody who lifts heavy and with slow and focused efforts regularily, will find that these tapes are tough but more from a muscular endurance stand point.