Here is what you should consider:
1. Skill/Experience - Do you think you can work through the organizing process in an efficient and knowledgeable manner. Organizers do this all the time, so we have fine tuned our efficiencies and processes.
2. Cost – Of course with a DIY project you will eliminate the cost of outsourcing someone, but what other activities can you be doing with your time that is more cost effective for you and your family?
3. Time - This is the greatest barrier to organizing I have found. Sorting, decluttering, cleaning, reorganizing and removing donations all take great amounts of your time. How do you measure your time and what it is worth. Are their other things that would benefit more greatly from your time??