The free trial period is too short, with a busy working life & domestic responsibilities 1 week is not longer enough to trial zwift multiple times.
You can get 7 days if you like:
To keep the Windows/Mac version on par with the iOS version we released a small update today. Additionally, we’ve updated our game servers, website, and game ‘login’ screen to reflect our new free trial. From now on, unsubscribed users will be granted 25 km of riding per calendar month to try Zwift out, as well as a one time 7 day unlimited mileage trial.