There is no fixed number of relays that you should be connected to, as it largely depends on your preferences and requirements. Some users prefer to connect to multiple relays to increase their network reliability and reduce latency, while others prefer to connect to fewer relays to minimize their bandwidth usage.

As for which relays to connect to, it's generally recommended to connect to relays that are geographically close to you to minimize latency. Additionally, you may want to consider connecting to relays that are operated by trustworthy and reliable entities, such as Nostr itself or other reputable organizations.