Any larger apps will install under /opt (which is a symlink to /home/opt), which provides 2GB so should be enough. It's only smaller apps (or those in the -devel or -testing repositories which haven't yet been optified) which will use up the root filesystem space. There's also currently a bug when installing multiple applications where the downloaded data isn't properly deleted after installing (until after a reboot), which can lead to running out of free space temporarily. This should be fixed with the next firmware though.