After good start problems

My old tower had cracked, that's why I needed replacement. A completely new machine I did not, because I try to produce as little electronic waste as possible. Unfortunately, the spare part is genuine completely overpriced - but still clearly cheaper than a new unit.
But the first few shaves with the spare parts were running not well. It did not attack properly, the effect was weak, you had to press properly so was ever shaved and it was long. I was annoyed and thought the negative reviews here apparently were right.
But after a few days it was suddenly better, the razor had again grip and now he shaved with the new part as good as originally with the original part. Why it is like that? No idea.

Due to the poor performance in the first few days and the overpriced price there's a star deduction.