Well, in my experience (and I have renovated 3 homes, 2 of which were total gut jobs, plus dealt with oodles of contractors as a Strata Agent), I don't think you NEED an architect ($$$), but you might consult a contractor-designer if you're not sure how you'd like it to look. You need to know which are load-bearing walls, etc., and to avoid extra costs relating to wiring and plumbing. Mistaken designs needing fixes can really add up in both time and money.
I always got 3 quotes for everything and I kept a binder and a spreadsheet to keep track of costs and estimates. Also, references, BBB, etc. are a must. Word of mouth referrals can be excellent. And for the bigger jobs, like we had all new custom cabinetry installed in our kitchen, living room and bathroom, I went to visit 2 of his finished homes and called another 2 more customers. Another resource is where you buy your supplies; ie tile outfits know who are good, reliable tilers.
Also, there are a lot of new products out there - fire-resistant materials, for example. And always go with a licensed contractor who gets permits. There are new rules regarding, for example, how high your cupboards must be around the stove (ours is gas) that didn't exist before. Licensed contractors have liability insurance which is crucial if there are defects in the product, workmanship or installation.
If you don't have the time or inclination to be your own general contractor (which I loved doing), then you certainly do need one as they coordinate all the other trades so that the plumbing and electrical are installed in the right order, etc. You do have to pay them, but it saves a lot of headaches and money down the road.
I love renovations! I hope you do before-and-after pics