Scheduling your posts is a great way to avoid both of these problems and to ensure that your tweets are going out at the right times to receive the highest level of attention. Having social media posts consistently scheduled in advance will also keep your company's social media presence stable if you become ill or injured.
Many social media networks actually let you schedule your posts, especially if you have a business account(the scheduling feature on Facebook is particularly useful), but you're better off getting a social media management system you can hook all your accounts up to.
There are two primary social media management tools for scheduling your posts: Hootsuite and Buffer. Both tools can connect to several different social media networks including Facebook and Twitter. They also both have link shortening tools and analytics tracking tools for shortened links.
1) Hootsuite -- http://www.hootsuite.com
Hootsuite is the tool I've always used personally because it has a larger number of free features, most importantly that you're allowed to schedule a larger number of posts for free. You can also connect Hootsuite to several social media accounts for free. A generic monthly report on your social media campaigns is sent to all free accounts. You can schedule posts as far in advance as you want to with a minimum advance time of five minutes.
There are also multiple types of paid plans for businesses of different sizes, allowing teams to collaborate on social media and send each other internal messages about specific campaigns.
2) Buffer -- http://www.buffer.com
I've used Buffer once for a non-profit client and it is definitely a powerful platform. Its suggested scheduled times for posts are incredibly useful; when you sign up the site will automatically calculate the best times of day for you to be posting content. Buffer also has several excellent analytical tools. There are multiple paid plans for businesses of different sizes.
You can schedule posts as far in advance as you want to with Buffer but free accounts are only allowed to schedule 10 posts at a time. If you want to schedule posts further ahead you'll have to pay for one of the premium membership plans.
There are other social media management tools but I personally don't know anyone who uses them.
Do you use one of these tools or something different? How far in advance do you schedule posts?