Fcron is standard Linux scheduler used to schedule any command at any time. So this means that it doesn't have any limits and you can schedule just about anything. It is run as daemon in the background so you don't need to worry about it. You set it up with a config file which contains schedule.

Alternatives:

cron: Why not? - Cron is older than fcron and doesn't sleep between events.

anacron: Why not? - Anacron is used to schedule daily jobs, fcron can schedule to seconds.

ses: Why not? - Ses is buggy, buggy and buggy. It doesn't even uninstall properly.

Alarmed: It is the best alternative with a big plus (GUI), but also a big minus (no CLI). You can use custom command, so you can schedule anything, but you can't schedule it anytime (alarmed daemon doesn't provide an option for every possible time). It also needs python (because of the GUI, daemon itself doesn't need it), which consumes space.

You can use this simple yet powerful tool to schedule just about anything at anytime. You can schedule:

- profiles
- backup scripts
- resetting the GPRS counter every month
- disconnection and connection of mobile network or internet
- 3G/2G/Dual radio modes
- NTP update
- email notify/refresh
- brightness level
- locking
- rebooting
- your own scripts
- ...

The wiki entry covers why is using fcron the best way for scheduling events, installation and configuration guide and some scripts.