You can use contract by activating it in configuration > Sales > Contract manager

thank you ...

Different solution: see https://www.odoo.com/forum/help-1/question/how-to-create-recurring-invoices-1560

This is how it worked in OpenERP7. The difference is that the subscriptions are no longer under the "Tools" menu (which doesn't seem to appear in Odoo 8) but you can find them under Settings > Automation > Recurring Documents

I don't know the difference yet between those two solutions but I think the recurring documents is more flexible.

You install module account_analytic_analysis (Use contracts management) . If you create a contract, you will be able to choose  "Generate recurring invoices automatically"