Depending upon who you ask the question, "Should I wear a weightlifting belt?" you might either end up getting an emphatic "yes", a condescending "no", or a disinterested "I don't care." For instance, powerlifters almost obsessively use specialized weightlifting belts, while CrossFitters are proud to boast that they never do. Bodybuilders are split, with some believing wholeheartedly that belts are essential for both safety and performance reasons, while others believe them to actually INCREASE your risk of injury over time. Olympic lifters don't really care either way.
Given all of the advocating from both sides, it can be hard to parse out an easy answer to what seems like a simple question. There are distinctive the pros and cons worthy of consideration.
A belt may help prevent injury to the lower back while performing heavy lifts.
A Belt can actually increase performance capabilities.
A belt could possibly inhibit motor learning in the abdominal muscles.
Wearing a belt could mean that your lower back might not become as strong.
All of the upsides to wearing a belt boil down to the concept of intra-abdominal force or pressure. One study found that "Intramuscular pressure of the erector spinae muscles increased significantly by wearing the abdominal belt during Valsalva maneuvers and during maximum isometric lifting exertions". In short, by increasing the pressure in the abdomen, you better stabilize the whole area, which makes for safer working condition for the spine and a significant increase in your ability to lift even heavier weights.
Another study showed that wearing a tight and stiff back belt while inhaling before lifting greatly reduces spine loading. This is caused by a moment generated by the belt rather than by the IAP (intra abdominal pressure, which suggests that there may be even more reasons why belts are beneficial.
Ultimately, you should take a look at the statistics, and the correlation between those who wear belts and those who are crazy-strong is very high. The bottom line is that wearing a belt is a highly personal decision, but it shouldn't be taken too seriously. Try wearing one a while, and if you feel more confident wearing it, wear it! If you find it awkward and uncomfortable, don't. All that matters is that you never let someone ELSE decide for you.