|As with all other purchases that we will make in the course of being a mom, we have to consider a lot of factors the time that we decide to buy a diaper bag.
First, the size. They come in various sizes so it's important to know if you'll be needing a small one (for short trips, to the mall, perhaps) or a big one (for longer periods of time, like a weekend getaway). Of course it's good to have one of each so you won't have to stress on carrying a small bag for a long trip or a big lumpy bag for a short trip.
Second factor is style. What will you be most comfortable with? A hand carry diaper bag? Maybe a backpack, or a sling one? Perhaps a shoulder strap? This is essential because you need to be at ease with how you carry the bag.
Third is the design. Obviously, most daddies wouldn't be caught dead with anything slightly feminine-looking on a diaper bag that they will be carrying most of the time (although some just don't care), so "daddy diaper bags" (as they are more commonly called nowadays) will be the best buy.
Features are also important factors. Multiple compartments would be great if you have a lot of items to load in the bag. Fold-over tops are best if you are a one-man army for easier access to the essentials inside the bag when they are needed. Side pockets for holding bottles is also a must if you are bottle-feeding (you wouldn't care for that feature if you breastfeed full-time). It is best that you look for a diaper bag that is easy to clean inside and out.
Lastly, price is an important factor to consider. Would you be willing to fork out as much as a couple of thousand dollars for a designer diaper bag like Louis Vuitton, or would you settle for the basic diaper bag that's around the $15-$30 range?
All these (and if there are more, feel free to point it out) are stuff that we should think through before deciding to buy a diaper bag that will fit our needs. So. Consider first and happy buying!