The critical decision you need to make when deciding whether to build or buy a storage shed to address your storage problems should be determined by two factors-

1. Your budget

2. Your ability as a handy man or woman.

Building your own storage shed should in theory be cheaper than buying a ready made shed or shed kit. However if you are not that proficient at do it yourself tasks then it may well turn out to be an expensive project in the long run.

You will need to address such critical decisions as what sort of shed foundation you are going to use, what materials you need, have you a set of plans with step by step guides, do you need permission for it from the local planning board or resident's association and so on.
Getting down to the nitty gritty will involve a number of problematic areas such as what type of roof you need, how many windows if any, what type of door and what width do you need and many other decisions. It is a very doable project but you do not want to spend your time chasing to the hardware store at the weekend to discover it is closed just when you need some tool or lumber or screws etc.

Buying a shed kit might provide a simpler solution and there are many providers of sheds who will let you assemble your own with panels pre punched or drilled and a set of plans and step by step instructions.

You can also purchase ready made solutions for your storage needs such as Arrow metal sheds or Rubbermaid sheds. Rubbermaid do a huge range of sheds which can be adapted to various spaces and with different types of sliding lid which allow you to maximize your existing space.

Another decision you will need to consider is the longevity of your storage shed and whether it will need to be painted or treated every year. You won't have this problem if you purchase a vinyl or metal storage shed.

Aesthetics may also play a part in your decision and you may be concerned that if your shed is highly visible then it may clash with the appearance of your home and perhaps even detract from it's value if your's is a particularly hideous structure.

These are some of the considerations you will need to factor into your thinking as to whether you should buy or build a storage shed.