Maximize your free hard drive space. Uninstall unused programs and delete old data files. If possible, save audio and video files to a different computer or drive. Musical instrument digital interface (MIDI) files are an exception, as they are quite small and rarely cause storage issues. Free space is like blank tape. The more you have, the more time you can record.
Defragment your hard drive regularly. If free space is unorganized, the drive works harder to store data and increased access times may reduce the effective length of audio you can record at one time.
Reduce bit rates and sample rates to reduce the size of recorded audio files. The trade-off is quality. Consider your final product. If you are recording for a CD, a 16-bit, 44,100 kHz sampling is adequate as a recording level. It's true that higher bit and sample rates dithered to CD quality can give better audio performance, however lower rates produce smaller files and increase recording time.
Reduce your track count by combining sources on one track or a stereo pair. You may have eight or more microphones on a drum kit, for example. These can be combined to a stereo pair in a mixer prior to recording. This will require 75% less hard drive space than recording each mic separately. While flexibility in late-stage mixing is lost, additional recording time is gained.