Well there are a number of really good reasons to have guest posts on your blog and a few pitfalls...
Varied content - you can't be an expert about everything and even if you are, it's always good to bring in fresh perspectives and new ideas
Time Off - Rather than spending your entire vacation blogging or hurrying to write all of your content before you leave, asking your readers and fellow bloggers to share their expertise with your readers will free you up to enjoy your vacation.
Help - When life hands bloggers a difficult time, you sometimes need to put family first - that's where having a blog friend or two step in to help you develop new content and promote your blog comes in handy!
Networking - Most people who guest post on your blog will share their good fortune with their readers which drives new traffic to your blog - creating a win/win partnership
Now, not all guest posts are created equal - and remember it's still your site so YOU define the content so when you ask for guest posts you need to be clear on what you want.
Unsolicited offers to guest post on your blog often come with affiliate links or links to for profit business - this really isn't guest posting so much as sponsored content which has it's own set of issues (ooh... another article potentially?)
Guest posts should link to the writer's website and/or social media but should not contain any 'money making' links
Content may need editing - even if it has someone else's name on it, it's on YOUR blog, so make sure you read the post carefully for content, typos and controversy that you don't want being associated with you - even if you've asked for a guest post it's okay to ask someone to edit or not to publish at all if the post isn't right for you.
Copy and Paste content - you can find any number of free plagiarism checking websites to make sure that the content is fresh, but you can also take a random paragraph and search it in google by adding "quotes" and seeing if the whole sentence or paragraph already appears on the web
Having a guest post policy and directions you can share is a great way to stay true to your blog and be fair to those who want to offer you content - here's what I use at www.actingbalanced.com:
Guest posts can be up to 500 words with an additional 100-150 word author bio and can contain links to your blog or website and social media.
Photos and graphics must accompany the post as separate files (.jpg, .png or .gif files) or as direct URL links to be placed by me
All posts will be read by the blog owner for issues related to content and presentation and I reserve the right to edit or not to publish at my discretion
The blog post must contain at least 50% new content, unless otherwise agreed in advance and may be subject to plagiarism checking
No affiliate links or promotion of for profit businesses in guest posts (I have a separate sponsored guest post policy too) - I break this rule when I solicit specific experts for content posts, like my Autism Awareness Month event and allow them to showcase for profit businesses at no cost but I do add a disclaimer to all of my posts during that month with such details.
I personally love having people guest post on my blog and sharing their time and talents with my readership so if you're interested in checking out Acting Balanced to see if what you write would be a good fit for my blog, I invite you to stop over!
Having guest bloggers on your site can be a win-win situation as long as you know your limits and manage your blog the way you want it to be presented. Please comment below if you have any other suggestions for bloggers who want to invite guests to post on their blogs.