Maybe set up a cron job?
minute hour day-of-month month day-of-week command
For all the numbers you can use lists eg, 5,34,55 in the first field will mean run at 5 past 34 past and 55 past what ever hour is defined.
You can also use intervals, they are defined like this: */20 this example means every 20th and if in the minutes column this will be equivalent to 0,20,40
So to run a command every monday at 5:30 in afternoon:
30 17 * * 1 /usr/bin/somedirectory/somecommand
or every 15 minutes
*/15 * * * * /usr/bin/somedirectory/somecommand
or pr user
*/15 * * * * root /usr/bin/somedirectory/somecommand
Note that the day-of-week goes from 0-6 where 0 is sunday.
You can see the contents of the user crontab with crontab -l.