First, it is good Netiquette to accept that email is asynchronous. Then, don’t expect an immediate response. Given, we might not read it.
Waiting Netiquette Personal Email
Next, asynchronous is an adjective. Then, describes something that is not in sync. It follows, a gap between when it received or read.
Email is not synchronous. Thus, recipient may not respond to a message. Therefore, may not know a message is coming. Response not required. But, possible. A routine check is a requirement. In order to respond to messages appropriately.
Personal Email Waiting
Situations for sending follow up email messages and resorting to other methods of contact vary. A follow up email may be in order if there is no response after one day. A phone call is synchronous. Telephone contact raises the importance of the message.
In general, check at least once a month. Given, some people send time sensitive information. Checking personal email once a week is preferable. Daily use of personal email is becoming standard.
Accept that it is asynchronous because we cannot expect immediate response.