For example, the content on Super Weddings is useful whether you're organizing a wedding today or next year. All the content on the site is created accordingly. To make things easier for the audience, it is separated into categories to make it very convenient for the reader to find what they're looking for. This, of course, is also very good for SEO.
If you have a good idea for an app, and the skills to create it, then producing your own premium app can be profitable. However, with so many free apps available, it may be hard to convince people to pay. If you want to go down the premium app route, consider having a basic free version to encourage people to download the app in the first place. You can then provide the option of upgrading to a premium plan once users realize how useful the app is.