The default timeout for a plugin is 10 * timeout (Admin Settings).. so usually 600 seconds, or 10 minutes. If a plugin needs more time, they can set: timeout=1234 in the plugin.conf to allow a higher value for the alarm() function. The maximum value is 4294967295, from UINT_MAX. The value must be greater than 0, as unlimited is not allowed. Just as example, 4294967295 seconds is 136 years.. so your not likely going to want a value that high. Set a number that's comfortable enought, but doesn't last forever, else you may end up with hanging directadmin child processes, waiting around for a plugin to run for 136 years.. and eventually clogging up everything, preventing you from logging in. At most, I'd say one or two hours should be sufficient for most cases.