We are a group of 4-6 adults planning to spend 7-10 days exploring Turkey’s western region, particularly ancient sites from Izmir to Antalya. The history of the sites is important to us, so we want to have a guide or guides. The question is: do we hire a custom guide (with car) for the entire trip or hire local guides for each site? What guides or companies would any of you recommend? What sources do people use to find local guides? Have travelers found that a custom multi-day tour was worth the money?
I cant help you with names, but I can tell you what I would do given where you are going and what you are interested in. I would do a bit of research and find a good Turkish travel company and turn it all over to them then sit back and enjoy.
It depends on what sites you are interested in. It should be pretty straightforward to find good local guides for places like Ephesus. For more obscure places --- and there are plenty of them in that part of Turkey that are worth visiting -- finding good guides might require a lot of logistics and vetting.
Of course, the more obscure places are where one most needs a guide. The big sites like Aphrodisias or Perge are well signed and have good audio guides. The off the beaten path sites, like Termessos, have almost no signage or interpretive info, and you pretty much have to figure it out for yourself.
I did not hire local guides during multiple stays around Antalya, largely because my schedule was too unpredictable. I did take a look at https://www.toursbylocals.com -- I can't vouch for the quality one way or the other.
With 4-6 people, I would probably arrange a private tour for the whole duration. I would start by looking at SRM travel, which I believe is the company that Rick Steves uses. We did something similar to that in Jordan and Israel a couple of years ago. It was expensive, but a single company took care of all the logistics.