In the EastWest sound libraries manuals it us written that SSD performaces drop after being more full than 70 percent. And a big drop in performance after 90 percent being full. I knew about the 90 percent thing, but the 70 percent thing is new to me. How about the experiences here in the forum?
I recently only discovered this, when reading this article (I didn't actually finishing reading it to be honest):http://www.howtogeek.com/165542/why-solid-state-drives-slow-down-as-you-fill-them-up/
I can confirm all, but actually prices are so low that best oprion is to by a brand new SSD when you reach 70% (off course only if you really need full speed like video capture in 4:4:4 or similar, in daily use it's not so important)
This company states on their website (somewhere in there, if you look for it) that their Mac SSD drives do not drop off in speed....
I have two of them (one replaced the optical drive) in my MacBook Pro now with amazing results so far, but not 70% full yet... Will keep an eye on this and let you know what happens.
For those who have Samsung 840 Evo http://www.anandtech.com/show/8617/samsung-releases-firmware-update-to-fix-the-ssd-840-evo-read-performance-bug