There are many reasons why it takes 30 days or more to close on a house. If you plan on applying for a mortgage loan for example, you will have to wait to be approved which can take up to 30 days. While you wait to be approved, you will schedule a home inspection to make sure the physical structure and wiring of the home is up to par. It can take up to 15 days for this process. The lender then hires an appraiser to determine the fair market value. The process of scheduling an appraiser is the same as the inspection, up to 14 days. This is due to availability, especially in a smaller town with fewer appraisers.
Once the loan is approved the lender will have to review it to make sure nothing has changed during the underwriting period. As the buyer you would have to conduct your own title search to ensure there are no issues or liens with the property. Once again, another 14 days. Do you see how long closing can take? To speed up the process a little you can always get preapproved or prequalified before you start your homebuying process. This will cut down some of the waiting period but either way you want to make sure all the vital paperwork is squared away.