Shall I buy it? Or Can lease it?

Each edition can be purchased as a perpetual or lifetime license with USB dongle. So you will be able to use your license without any internet connection.

After 12 months, we will propose for you to renew the maintenance services which includes support & updates. If you do not wish to renew it, you will be free to continue using your current version of eDesigner software for lifetime, but without updates or support services.

You can lease the eDesigner Pro+ or Ultimate Editions software on an annual basis and benefit upgrades during the rental period. Each year, you will decide whether to renew the lease or end using eDesigner software.