Make sure that if you decide to roast, it is for the right reasons and takes into consideration the skills necessary to excel at the craft.
Using fresh coffee is important, but the definition of "fresh" is something that can be a little confusing. The general consensus in North America right now is that coffee is best used within approximately 14 days after leaving the roaster, and typically not before the 3rd or 4th day, while the coffee degasses. The guideline can be shifted +/- a few days depending on the style of roast, extraction method and varietal of coffee... and of course, personal preference. Any reputable specialty coffee roaster will be aware of these parameters and will likely have their own interpretation, so unless you are located in an extremely remote area of the world, I do not see that coffee freshness alone as being a key issue for self-roasting.
The larger benefits to roasting that I see in most situations relate to 1) quality control, 2) profitability / new market opportunities and 3) the ability to project one's brand image.
1) Quality control - The saying "nothing worth doing is easy," may apply here. The finest restaurants make their own base ingredients and sauces, some even baking their own breads so that they may meticulously control all aspects of their business for a perfect experience. I had the opportunity to interview a multi-James Beard Foundation award winning (his wife also had multiple awards) that operate a successful high-end restaurant in North Carolina that told me he bakes his own bread "because it was more difficult," thereby making his restaurant more unique.
That being said, you must be certain - absolutely certain - that coffee that you are roasting is better or otherwise more desirable than that which is available wholesale elsewhere. There are some phenomenal micro roasters around the country (and around the world) that specialize in the craft - it's all that they do, and they do it well. You must be certain to understand some fairly intricate (not necessarily complex, but involved) details in order to bring out the best in every batch. Anyone can operate a roaster, but a skilled roastmaster acts like a chef that can objectively evaluate each green coffee he or she purchases, develop a roast profile that accentuates the best nuances of those coffees and, as appropriate, combine those flavors to make unique creations.
If you don't know what you're doing, you will do much more damage than good by attempting to bring the roasting business in-house.
2) Profitability - If the business is structured and operated properly, it will be more profitable for you to purchase raw ingredients and roast the coffee yourself than it will be to purchase prepared goods elsewhere. That's obvious. Beyond that, roasting your own coffee opens a new vertical market: the ability to sell wholesale coffee for profit. Whereas it is not a good use of time to purchase and resell another roaster's coffee to your retail competitors, as the roaster, it may become a new lucrative component of your business and has the potential to become the largest profit center.
Again, there are caveats attached to this line item; you must have sufficient resources (staff, funds) to build the wholesale business as a self-sufficient entity in order for the wholesale business to blossom and it should be marketed in a manner that compliments your retail brand message, which is a good segue to...
3) Brand image - Practically anyone can walk into a wholesale coffee roaster's office and walk out with an agreement to supply their coffee. Granted, the better roasters have quality standards that they establish for their wholesale clientele, but from what I've seen, those tend to go out the window when cash is in hand (especially when companies are hurting for new business). Roasting your own coffee gives you the ability to have something that is not available elsewhere. You control all elements: the green coffee, how its roasted, blended, packaged, etc. which can be a distinct competitive advantage. Furthermore, controlling the roasting side of your business gives you intimate experience with your product (you made it) and frankly, implied credibility that you have an idea of what you're talking about with customers.
As with the other "pros" above, it all goes out the window if your coffee is no good. My recommendation for the average retailer that wishes to operate a single shop as a form of retirement or therapy is to avoid roasting; there are many others out there that can do it better. However, if you are adequately capitalized and have a plan for the future in the specialty coffee business, roasting is the way - the only way - to go. There is a reason that you cannot name many major retail operators that do not roast their own.