I figure, if it works ,don't fix it. I have not had to replace a fuel filter on any vehicle since the 1960's. Fuel is already filterd several times before you pump it. Now, having said that, is there any reason to believe that 4runners are any different? Mine has 80,000 miles and runs smooth. If it turns out to wise to replace it;is it difficult?

 

4cyl or v6? Both take work, but are doable.
As far as the gas being filtered, keep in mind it is then stuck in a tanker that has been opened and closed time and time again with the fittings being exposed to grit, the tank at the gas station most often has the valves below grade and get grit in them, the nozzle for the gas pump sits out in nature with, you guessed it, more grit, the gas cap sits in an unsealed area that picks up grit which gets stuffed into the filler tube as you pump the "filtered" gas into it. There is plenty of opportunity for the fuel filter to get clogged and the potential performance increase is worth the effort.
I know many people say that the little sock around the intake on the fuel pump is supposed to take care of that, but I think it only takes care of the larger particles and the finer matter gets through to the filter.
As an aside, way back in high school I worked in a gas station for a while. When I had to dip the tanks to get an idea how much was left in them it never failed that there was a lump of mud on the end of the stick. The gas may be fairly clean at the refinery, but it gets dirtier at every handling.

 

Thanks Farenheit. Sounds like I have been lucky. The vehicle in question is a 6 cyl. Is changing the filter something best done by a pro?

 

Nope. You haven't been lucky. The performance of your previous vehicles probably diminished over time... so subtle that you may have not noticed. You may have had to rev your engine more to get power, had to take hills in a lower gear, suffered slow starting and maybe even bucking. You may have thought the vehicle was wearing out or at least wasn't as much fun as it used to be. At any rate, the fuel filter on my Corolla (257k miles) has to be changed a couple times per year (about a month after they do the winter/summer fuel changes) and the 4Runner every couple years. Each time, they are filled with gunk. I buy my gas primarily from Sam's Club and yes, it is filtered at the pump. Dirt still gets in.
Do a search on fuel filter and there was a great write up earlier this summer.

 

I changed the fuel filter on my 95 at about 90k and it was very clogged. I blew through it backwards and a bunch of sludge came out. A shop will charge you way too much to do it. It's not terribly hard to do yourself. I reccomend unbolting the crossmember for more space when you do it. Make sure you soak the threads with PB Blaster first.

 

Use the search. There are many good post that go over this in detail but I will summarize for you:

1 - Plan ahead
2 - Examine the cross-member removal method and determine if its for you
3 - Buy a Toyota Filter
4 - Use the proper flare nut wrenches
5 - Loosen the gas cap first
6 - Be prepared for gasoline to get on your upper body in limited quantities

Armed with this knowledge - do it yourself. I did mine myself and it sucked but I didn't know about the gas cap removal trick and ended up wearing 2-3 gallons of fuel that vacuum bled out while replacing the filter.