In general, your ISP mail box should be sufficiently large to cover the period.
However, some ISPs offer tiny mail boxes with their cheapest programs. A friend has a phone/cellphone/DSL package that includes only a 2MB mailbox (the phone company’s cheapest package). This little mailbox fills up when someone sends a couple pictures. Most ISP’s these days offer 10MB for emails. [Gmail offers 1.7 GB so you can get a LOT of mail.]
Your mailbox will hold the email until you take it. But, if the mailbox gets full, it will start bouncing emails.
If you want to STOP emails from coming while you’re out of town, then you’ll have to handle that with each newsletter and mailing list to which you subscribe. Realize, though, if you do stop (unsubscribe, usuallY) from newsletters, you won’t get the emails that would have been send during that period. And, you’ll have to sign up all over again.
Most of us just let emails build up in our mailboxes. When we get home, we let the computer download the email.
Of course, you could even go online and read it via webmail — and delete all the junk you really didn’t want, in case that would be faster. If you have a dialup account, that’s a good step.
Bottom line: There is no “post office, please hold the mail” necessary — your ISP will handle that automatically. Most newsletters and mailing lists do not have a “put on hold” function.