This frequent process should be handled one time at least every week to keep your page rank and even to raise it.
Content you will add (as posts and pages) will also keep you in contact with your site and with your visitors.
You need to have new ideas all the time, you need to have kind of talent in writing that enables you to attract visitors reading your posts till the end.
In real world lot of websites builders don´t have this imagination to find new ideas every week, lot of them have not the required writing talent(or simply have no time).
In these cases there are some other creative methods which can be very helpful as a source for your website content:
1. Using PLR (Private Label Rights):
Buying PLR articles is totally legal as you can buy all the related rights of these articles from the writer himself, so you can do what you want with these articles, editing, modifying or even selling them.
There are different ways to do that:
1. Buy a PRL membership at www.PLRPro.com site: You will be able then to buy the articles for very low cost, the downstairs here that you will usually do not get to choose your topics.
2. Buying individual PRL articles packs from websites without membership fees: You will pay more for each article but you can choose the topic.
3. Searching related forums where you can find some people selling their articles there
I suggest that you take your time in searching different PLR sites and look for the quality of them, some of them are based on targeted keywords which can match your requirements.
In general PLR articles have good quality when comparing with other sources, but on the other side they may be used from other websites.
2. Personal Blogging:
I mean here that you can write your articles in your native way such as when you writing an email to your friend or a letter to some relative.
This way may leave a better impression n your visitors as it will show your personality and may make them more comfortable with reading your blog/article.
If you don´t want at all to spend your time on writing process you can hire some one to do that instead of you.
You can use many websites which are specialised in connecting between you(as a publishers) and the content writers (freelancers).
i Suggest you these two famous websites:
1. www.freelancer.com: where you can hire someone (per hour or per action) to do lots of works for you (not only content-writing but all other website related-tasks like SEO design, …etc).
2. www.elance.com : You can get almost the same services.
In these above two sites you will post a project and describe what you want exactly, and soon you will get offers from many freelancers offering you their services and prices so you can chat with them first and then make a deal.
I recommend that you deal with recommended freelancers (they have many stars in their profiles and positive reviews also).
You can discuss the price there to reach your target budget, but try not to look only on the price as some of them may give you bad quality job.
4. Using Article Directories:
I must tell firstly that i don´t recommend this method at all.
In this way you can use the articles which are showed in some specialised Article Directories websites (like www.bussle.com, www.goArticles.com …etc).
You can find a huge range of articles which cover almost all categories, you can select any of them and insert it in your website for free! … well but it must be as-is.
You can´t change any word or link in this article, no editing, just copy and paste.
Downstairs in these method are clear:
1. You will get a Duplicate Content Penalties ( Read: What is Duplicate Content? article) as many other sites will use the same article, and your article will be treated as a Supplementary results.
2. You can´t insert any affiliate link into the article content.
3. You are even forced to link the sites which are connected previously to this article.
4. You can´t make SEO for this article.
5. Make a Video/Audio Content:
As some people prefer to listen or to see than to read (i am one of them) then if you don´t like to write because of some reason you can record your speech about some topic, you can do this alone or as a conversation with another one (this partner may be an expert in your topic field).
You can talk for a long or a short time and in the both cases you will save a lot of writing process as each one hour conversation equals about 40 written pages.
Once you record this conversation you can hire some freelancer (from one of the above mentioned freelancers websites) to transcribe it for you( in general it will cost you 20-30$ for one hour transcription).