After much back and forth, I have now decided to use a SSD for my MacBook Pro (13 Mid 2010). The decisive factor was the price that undercut my pain threshold. Since I wanted to install new Mavericks, some on the program. So first backup with Time Machine, then the SSD in a USB enclosure and formatted. Then the installation. Instructions are available on the net so enough. So went smoothly. When you restart hold ALT key and connect to Wi-Fi. Then Mavericks is downloaded and installed from the store. Time Machine Backup played back and everything is as before. STOP! Everything? No, not all;) The box runs like the devil: Start earlier with HDD (7200 / min) for about 1 minute. After having SSD is the boot after 13 seconds !!! Completed. Madness. Never again HDD. So, then still: Trim turned on, HDD sleep mode off, Sudden Motion Sensor turned off, shut down local Time Machine backups. In the following 4 years