What are you renovating? Any photos?

I'd pick one room that feels like it's not working for you or no longer fits your style. That will keep it from getting too overwhelming.

However, if you think you may want to overhaul your whole house, color-wise or whatever, then a designer could be a good idea, to help ensure that the new look carries through from room to room.

Also depends on whether you're talking new kitchen/bath finishes ($$$) or just new paint ($) or even just changing up your furnishings. The latter two might make a huge difference to you but have little impact on home price; the former might affect value if you're selling soon, but otherwise are probably more for your own happiness soon (since trends are so likely to change again)...

Hi, if you hire a designer, many will have references or hire their own contractors to carry out the work you want done. With that said, an experienced contractor can also provide a lot if guidance on what design/features would be good for the age, style and area where you live. Who you decide to work with can really depend on your budget as well, since designers will need to cover both their fees, plus they may arrange to pay the contractor directly from your budget (potentially adding an upcharge), rather than you paying the contractor directly.

I would recommend planning a budget or range to stay in before hiring anyone, as well as, determining what needs to be done vs. what you want to get done. By setting a budget, you can give yourself a starting point to see how far your money can go. As for over-improving, I understand the concerns, and perhaps refer to town records and Realtor.com to get a rough estimate on the current value of your home and see what comparable homes in your town have sold for over the last 4-6 months.

Good luck with your renovations! I hope you share pictures of the progress. If you share your region, you may also get some great advice and professional referrals to help get you started.

In addition to the comments above, there are some great Decorating Guides on how to start right here on houzz.

https://www.houzz.com/magazine/decorating-101-how-to-start-a-decorating-project-stsetivw-vs~26609229

https://www.houzz.com/magazine/decorating-101-how-to-choose-your-colors-stsetivw-vs~28100106

https://www.houzz.com/magazine/decorating-101-do-it-yourself-or-hire-a-pro-stsetivw-vs~27152464

Spend some time gathering inspiration photos so you can show a designer your preferences. I am a big believer in hiring a professional - at least for consultation to start.