~Re-branding can be a good thing if done correctly but it also depends on what exactly you are trying to "re-brand" if it is a name change, logo, new or more products/services you may be looking to offer, those would determine if it is even necessary.
I can't say when the time is right because everyone is different & have their own thing going on. However, if you are unsettled with whatever you currently have maybe re-branding is an option or, maybe you just need a website/social media makeover graphics wise instead of total re-branding. Sometimes, some new creative art makes everything feel brand new & sparks life into something that was already fine to begin with. (^_^)/ (o^_^o)
Reason Studios formerly Propellerheads recently re-branded their company name, domain, logo. . .I personally think it works. The logo has a much more generic but modern look to it & the name just makes sense seeing as most people referred to it as Reason more so than Propellerhead.