Three item checklist before buying a theme:
- Appearance and Functionality
- Number of Sales, Reviews and Ratings
- Updates and Supports
Appearance and Functionality – This pretty self-explanatory where you should pick theme which you like the look of and has the functionality you want. Because a theme can have so many combinations of functionality and appearance, you may not get everything you want in one theme. Remember functionality can be added by finding the right add-on plug-in, and unless you’re willing to edit the PHP and/or CSS code yourself, it’s probably more important to find a theme that matches the look you are going after.
Number of Sales, Ratings and Reviews – like buying anything online, these are your basic research criteria. Number of Sales is actually a two sided criteria. Not only are you checking out how well the theme itself is selling, but you also need to check out how well the developer’s other themes are doing as well. A good developer will have multiple themes with high number of sales. In terms of ratings and reviews, these speak to the popularity of the theme. Of course 5/5 stars themes would be awesome, but if it’s only rated by a few people, the overall results could be skewed. 
Whereas if the theme has 4.73/5 based on 8034 ratings you know the popularity and rating of the theme is a bit more true to life. Read reviews. Specifically look for good AND bad reviews. Reviews give you a much higher level of detail which a simple star rating cannot on how good a theme actually is. Now once you start reading the reviews, you will notice that sometimes the review is not only about the theme selected, but also about the developer (leading to next topic).
Support and Updates – Now what happens after you buy a theme? Support is becoming a more common thing these days. Like I mention previously, when you start reading the reviews, you will notice that a lot of reviews are about the developer and not just about the theme itself. These reviews are crucial as this will indicate how responsive a developer is when you run in to problems using their theme. Also a good theme will generally come out with updates. Now updates can come in the form of new functionality or updates/fixes to existing ones. A theme that is continually updated means it is going to have better longevity as it will continue to work with newer versions of WordPress. And when your theme is updated, usually the developer will allow you to download the updated version of your theme and even include instructions on how to update your theme safely.
Now you are probably thinking, if I buy a popular theme, wouldn’t my site look like everyone else’s? Remember a theme is only a template for building your site. For most of the popular themes, they are popular because there are lot of customizations and functionality which means no two sites built are going to be exactly the same.
Posted in: Beginner's Guide, Themes