Lot's of my friends now have new smart phones, and the first thing I do is suggest creating a gmail account.
When they ask me why, I go through the following explanation, so in future, when the question is asked, here is the answer.
The majority of my friends/customers have simple pop3 accounts, and many of these mailboxes have a relatively small size limit. When they get their new phone, they want to make use of their ability to receive/reply to and send email from the new phone. Most people manage to set this up quite easily, but the next day they check and the email is gone from the phone, and some days they think they get email, but when they check there is nothing there.
What has happened is that they went home and turned on their laptop or PC and opened the email client (Live mail / Outlook / Outlook Express / etc) which dutifully sucked down all the email and removed it from the mail server, or if the PC is left on with the mail client running, email will be downloaded and deleted from the server on a regular basis.
Now we could simply either set the email client to not delete the emails from the mailserver, or change the account to imap instead of pop3, but this can cause problems down the track when the mailbox overfills (whilst many ISP's have become more generous with their mail storage limits, most have not). So we create a gmail account, and we get the gmail account to fetch all the email from the normal email account, but not delete it from the mail server. Now set your "real" email address as the default email address (although many simply start using the gmail address because it will not change when a new ISP is chosen), import your contacts from your email client, edit and update contacts..
Now, on the smart phone/tablet we go get the gmail app (on most androids it is already installed) and simply set it up to access the new gmail account. From now on you'll magically have all your contacts available, you'll have your email and if you choose to make use of it, you'll also have a great calendar for reminders, events, etc.
As a by-product, you'll also have a really good backup of your emails, because your email client on your PC will have one copy and your gmail account will have another.
Gmail currently offers more than 10gig of storage so there is little need to delete emails, but I frequently use my PC to access gmail and bulk delete every email I know I will never need again (it's just easier than using a phone or tablet), I also take the opportunity to create "groups" in the contacts (so I can email multiple people easily) and update my calendar.