Two situations might require that you change the timeouts for SLP discovery requests:
If the SLP agents are separated by multiple subnets, dial-up lines, or other WANs, the network latency can be high enough that the default timeouts are insufficient for a request or registration to be completed. Conversely, if your network is low latency, you can improve performance by decreasing the timeouts.
If the network is subject to heavy traffic or a high collision rates, the maximum period that SAs and UAs need to wait before sending a message might be insufficient to assure collision-free transactions.