Sorry to post off-topic, but all my favorite Hawaii owners appear to be on this thread. If we're staying at the Hyatt for 4 nights (as part of a multi-islnad trip), do we need a car ... taking into consideration the taxi costs to/from the airport and parking costs at the Hyatt (guessing $25/day or something like that)? We're going to be doing a lot of exploring on the Big Island and Kauai .... and are sort of thinking as Maui as the "relax by the beach/pool" part of the vacation. Would we miss anything great?
If you've never been to Maui before it's a great island to explore areas like Kapalua, Wailea and Hana. However for a 4 night visit I think you could be very content just staying at the Hyatt. You can walk to Whaler's Village for restaurants & shopping. There are shuttles available into Lahaina.
I've never taken the shuttle from the airport at OGG, but my DIL took it last spring for around $60. I doubt the second passenger would pay the same price.
I've always rented a car in Hawaii but my last trip to Maui I didn't. My friend stayed with me and she had a car. I went with her to the grocery store, Kapalua, Lahaina & Wailea, etc. but kept thinking to myself "I'd be fine here without a car". She offered me the use of her car or to take me places but I never saw the need. I used the shuttle from the Westin Villas to the Westin Hotel several times.
Considering the expense of a car, parking & gas and that you intend to relax by the pool/beach on Maui, I would suggest you'd be fine without a car.