Events are important. Creating excitement and shaking things up always work. The operative words here are "creating" and "shaking".
A banner that flies on your store for two years means nothing after a month or two and probably fades and makes things look lazy.
Here's a suggestion. Pick a quarter and spend a few hundred dollars on a quality bright attention-getting banner. Here are some examples.
January, February, March. - If you have a gym or a fitness center to appeal to the New Year resolute.
April, May, June. - Pool Maintenance? Landscapers? Let's make a push to sign up new customers (for life?) this quarter.
July, August, September - barbeque, patio furniture, awnings. Create Excitement!
October, November, December - There is no business in the world that you can't twist into a Christmas promotion. (And if you can't I can so contact me). Halloween and Thanksgiving are both in there somewhere - so this is a great quarter to choose to hang a banner high!
Give them everything they want for a fiscal quarter. Don't let it out ahead of time, and take it all away at the end. Assuming you have a pretty good service/product at a decent price (which is kind of more important than what I am projecting here) you'll be Okay.
Don't take my word for it. Look at Shark Week and Swimsuit edition.