Synthetic oil?

I get my car serviced at Toyota dealership and noticed that they used synthetic oil at last change. Actually last three, but I am paying for it now. Charging about $3.00 qt. more than I pay for my RAV changes.
Maintenance manual doesn't say anything about using synthetic.
Asked if I only need to change annually/ 10,000 miles now and they said still need to change every six months/5,000 miles. Also, said I do not need to use synthetic in '05 RAV as it has a different 4 cyl engine.
Thought one of big advantages to using synthetics was longer time between changes.
BTW, I have a European car that uses synthetic and it is annually/10,000 miles between changes.
If supposed to use synthetic, why doesn't maintenance manual say this?
Don't mind paying for what I need, but don't want to pay for what I don't need.
Thanks.

 

Do you're own oil changes. At the interval you want too. Keep warranty in mind.

 

Yes synthetic is ideal for longer (mileage) intervals. Toy recommends doing every 6 months or 5k miles, there is a member on here with 330k+ miles on the 4 cyl and he changes his I think between 5k-10k miles. Regardless of the mileage though, in my opinion, I would change at least every 6 months or 5k miles, which ever happens first, and I use mobil 1 synthetic. The dealer is correct, you don't have to use synthetic oil, but why not if it's only a few dollars more a quart and it gives you peace of mind?

 

Uh, keep the synthetic, but do it yourself and save lots of this, $$$$...

I change mine about every 7500 miles, it costs about $25, I get the synthetic at WallyMart for about $19 (5+quarts), grab an OEM filter from the dealer ($5.41 + tax), bing bang boom...

Plus it keeps the dealers hands off the rig unless absolutely necessary...