There are two ways to save more money: spend less, or earn more. There are a bunch of great posts out there on how to earn extra money, in addition to what you bring in at your regular job. Looking for ways to make income on the side can be a great way to help you diversify your income sources, and to occupy your free time with an income-producing activity, rather than with high-cost hobbies.

• See Frugal Dad's post on Why Everybody Needs a Side Hustle
• Read this motivating guest post from My Journey to Millions on getting started with earning income on the side.

Believe me, I’m a serial hobbyist, and any hobby has the potential to be incredibly expensive once you get absorbed in it.

• This post from Get Rich Slowly gives some tips on how to make money from your hobby

The problem is, making money from your hobby almost always requires a bigger time commitment than you are currently making to the hobby. For example, I like knitting, and spend quite a bit of money on different yarns and patterns. However, in order to make much money from knitting, I would have to sit down and knit every night, instead of a couple of times a month.

Could you be spending that time improving your performance at your day job?

If you are just starting out in a fast-paced career, spending that extra time becoming the best employee at your new job could easily reap larger monetary benefits than any side income you earn. If you have free time when you want to be productive, spending more time reading industry-specific news, teaching yourself more advanced skills, or simply getting more work done could help you get raises and promotions much faster.

The guy moving fastest through the ranks at my current firm is not spending his evenings figuring out how to make $100/month from a blog. He is spending all of his work effort on his current career.

Is your side income intended to replace your pay check?

If I focused on making money from blogging, or from selling crafts on Etsy, I could probably make a few thousand a year. Making enough to replace even my starting salary (plus cover the extra taxes that come from self employment) is highly unlikely.

However, if I had a plan to launch a blogging empire that could surpass my earning potential in my current career, then focusing all of my extra attention on my entrepreneurial endeavor would be far more worth it.

When is pursuing side income a good idea?

If you are in a stable job, but with no room for advancement, it will be more efficient for you to work 9-5 at your day job, and devote your extra hours to developing side income. If you are starting out in a career where the top performers can expect a rapid promotion, then it may be more efficient for you to focus on your career first. (Especially because at very competitive companies, low or average performers may find themselves out of a job completely.)

OR If you run out of “mental energy” to put into your day job, but find that you have plenty of mental energy, or even feel more energized, from your hobby, like many of us bloggers have found, then trying to get some money out of that hobby may be a smart idea. This is generally my view regarding my blog.

If you’re going to do it anyway, you may as well make money

I like writing. I like my blog, and sometimes I write some paid articles for Associated Content too (Yahoo! Contributors Network now.) I have a couple of ad blocks, and make an effort to find additional readers, so that stuff I have already written has a better chance of earning me a few dollars later.

My blogging isn’t going to make me thousands, or even hundreds of dollars a month anytime soon, but I figure if I can get $50/month, it’ll be an extra $50 in my savings account that I would not have if I spent my evenings watching TV instead.

What do you think? Do you think that focusing on side income can jeopardize your career, or do you think a really motivated person could do it all?