If you use EEM applets with action syslog commands, the messages generated by those commands will be displayed in the same format as the debugging messages, regardless of their severity. This might be a problem if you decide to use different timestamps for debugging and regular syslog messages (or disable debugging timestamps completely). For example, the following configuration ...

service timestamps debug uptime
service timestamps log datetime
 
event manager applet Serial_Down
 event track 1 state any
 action 1.0 syslog priority errors msg "IP routing on Serial 0/1/0 is $_track_state"

... produces these messages after an interface failure ...

Aug 14 11:18:32: %LINK-3-UPDOWN: Interface Serial0/1/0, changed state to up
1d16h: %HA_EM-3-LOG: Serial_Down: IP routing on Serial 0/1/0 is up