A question only you can answer, but let’s take a look at some factors for your decision.
Change for the sake of change is simply foolishness. If your website is clean, easy to use, somewhat fresh, and has been redone in the past five years, a redesign may not be what you need. Part of human nature seems to be a resistance to change. Your audience, probably all human, will feel the same way. Change is jarring and harsh to many. It can be costly. It can eat up valuable time and resources. If you have an established audience that frequents your website you must change with caution. Make sure the changes are in their best interest, making things easier to use or find.
Changing because your competitor changed is not a good reason. If your site works for you and your visitors then the other guy’s site shouldn’t be a factor. Neither is the fact that you are simply bored with the site. You look at your website more than any of your visitors, make sure they are bored too before continuing. Not so much a “purple” person anymore and more of a “red” person - so what? Are you marketing to yourself?
Do not change because of one complaint, unless there are only two people visiting your site each month, in which case you have bigger issues. While it’s true that genuine feedback is hard to come by, changing based on one isolated comment is not good for you or your other visitors. If however you receive repeated comments about your site or a part of your site take the counsel into consideration.
Having said the above let’s look at the flip-side shall we? Was your site setup 10 years ago? Did your nephew do it while he was on break for the summer? Do you still have a “links” page? Dancing penguins, animated office furniture, or any cartoony anything? Are you on first name basis with all of your monthly visitors? Then you may just have a great candidate for a redesign! If the site doesn’t work for you, doesn’t work for your visitors or is just plain out-dated then you should check out your options. Design has come a long way in the last 5 years and is shifting still. If people aren’t visiting your site rethinking it is one of your options (there are certainly other factors here, but let’s stay within topic for now). There are a lot of great, easy, simple and cheap ways to update your site.
So have you decided you don’t need a redesign right now? Good, I’ll take the kids to the zoo, thank you and goodnight. Or maybe you have decided this is exactly what you need. There are things you can do to start the process before you call me or your friendly neighborhood web designer and you don’t have to know a lick of HTML, PHP or LOL. See my article How to Save Time and Money in Web Design.