This is a question that many multi-blog owners ask themselves. Most newbies, might want to go the free route first so that they can get their feet wet, see if this is something that they are really interested in, or if they can actually make some money out of it.
Others, who might have done this for a while have some experience with WordPress, an understanding and feel for the backend, can make a post, ping, setup pages and respond to comments. These bloggers are more likely to own more than one blog, because blogging can be very, very addicting.
These multi-blog owners might find themselves in a bit of a pickle when it comes to their newest site. They possibly are generating a bit of revenue from their other blogs but would now like to take it to the next level. They want to own a blog that has a bigger draw, that creates even more revenue than the others. This is the time that you should seriously start considering dipping into the pocketbook and purchasing a custom wordpress theme.
What are the benefits of a custom wordpress theme you might be asking yourself? There are many.
If your niche is a decidedly targeted niche, it would favor your blog to have a design that is catered exactly to that niche. Sometimes sites that do not accurately reflect its purpose can lose a lot of the traffic that it is working for simply because it does not look like what it is supposed to. If people click on a link expecting to see a sports site, yet it looks a bit feminine in style the likelihood is that the user will be clicking on the back button pretty quickly.
If you require special features or script enhancements that would otherwise not be available to the regular blogger you will definitely need to have a custom job done. You might thing that it would be a bit expensive but it is worth the extra money as the value that you will be adding to your site will return that cost many times over.
So when is it time to invest in a custom wordpress template? If you are at the point where you are making regular revenue from your blogging efforts, you should take a look into a custom theme. If you do not cash a regular check from your blogging efforts, you can probably get by with a free wordpress theme for a little longer. Once you start generating some revenue to pay for the site then it is time to start considering customizing.
Many people like the look and feel of a customized wordpress site. Added features could easily enhance it to the point of increased traffic. Increased traffic tends to lead to an increase in your revenue. I always consider that to be a very good thing.