How many PPCoins do I need for PoS mining?

I have been PoS mining for some time now and my coins are half a year old already without being spent. How many of them do I need to see stake once in a while? I just want to make sure that it’s working but currently it just looks like doing nothing.

edit:
I just lost a bunch of PPCoins and got incoming transaction of only a few coins with message “Mined balance will be available in 515 more blocks. Mint by stake.”
Will I get all my coins back after that or how is it logical that I lose more than I gain by minting?

It seems to be a bug. Don’t worry, the coins will be back to your balance after pos minted coins are matured.

Coins come back after 520 blocks, in about a day they will show under STAKE balance.

ok thanks. I now see the stake. Pretty much all of my balance is now in stake. What does stake do? Can I send it like normal coins?

They are in stake for 520 blocks. In this time they mature and cannot be used for payments.

Thanks, I think I finally get it then.