Not worth really ...

I compared it with the DM-denkmit powder and so as you can save from 20 to 40 ml of washing powder, but must give 10 to 20 ml of pure water softener. At least for the Dm-denkmit powder to get quite the same price.

Even if you buy the great skip washing powder at Amazon pays you plan: 60 washloads to a Dopppel pack washing powder endure and that costs as much as 10 euros. This is also not cheaper than good powder (Stiftung Warentest!) Powder of DM. Especially since you then the great powder as stain remover and Wassenthärter must add.

Conclusion:
Money really can not save you so. At least not if you already bought powder with good price-performance ratio. Even the Skip concept in total does not seem to be mad cheap .. It may be that it protects the environment more, so there are two stars.

PS:
"Protects the machine" is on the water softener. But one really needs but no means. Modern machine do not need protection against scale, although the Calgon and Skip would like to have different.