Yes. You can have as many subscriptions as you like.
You can't add more minutes to your subscription by buying the same one again, but if you run out of minutes you have a few options: you can buy a different subscription, upgrade to an unlimited subscription where available, or buy some Skype Credit to pay as you go until your existing subscription is automatically renewed.
If you have more than one subscription, Skype uses them in the following order:
- By subscription type – unlimited subscriptions are used first, then limited ones.
- By expiry date – subscriptions with the nearest expiry date are used first.