Well for me its better to save your bitcoins without certain percentage. Just hold it out until you don't need to spend some. But when the times of need comes, then just use and spend it so that you can now have the benefits of having a bitcoin. So that will really depend on how you'll use it but that's what I'm doing and its effective.
Saving is always good either fiat or bitcoin but saving bitcoin will give you higher advantage then saving fiat as the value of fiat will never grow in future but you can expect much higher price of bitcoins in coming years so whatever you save it will become more valuable as time move on and if you are in need of money in emergency situation then spend only that you require and rest keep it safe for future.
Yeah saving in fiat will be a wasted since inflation happens every year but in bitcoin saving will always be the best choice. Because it's already proven that the longer that you will be saving bitcoin, the higher value of bitcoin that can happen before you will sell it. Many of us are doing and it's really satisfying to see the profits.