For users who do not have a jailbroken iDevice, you have to reinstall the Cheto app every 7 days, otherwise it will stop working. This is a security mechanism from Apple, as your Apple account is only allowed to create a certificate for signing and verifying apps that lasts for 7 days.
If you use a jailbreak, you can follow the steps here to find out how to add our repository to Cydia and have a much more comfortable experience.
An alternate, albeit costly solution would be to sign up to Apple's Developer Membership which costs around $99. The certificates from paid Apple accounts last 1 year.