About how long
 

A friend is going to start running my bio. He has about 100,000mi on his F-350. Should he start with a bio mix or can he go right to B-100. I have run Bio since my truck was only a couple of months old so I haven't had any filter problems. I was wondering how many miles can he go before he can expect to change fuel filters. Does anyone have any other info on what else to prepare for or expect with the switch over.

Go straight to B100.. wont hurt a thing.

carry an extra fuel filter just in case.

Don't expect a plug filter.. I happens but its rare.
Do expect a smoother running engine
Do expect a less offensive exhaust smell
Do expect a financial savings.

I understand the Do's and dont's that you listed(thanks) but I was just wondering if anyone had an approximate mileage mark that I could tell him. Like eg; in 1,000 miles you'll have to change or plan on changing at 500 miles. People always say carry an extra filter just in case, I for one cant afford to do that because if I'm on my way out to dinner or work or something like that I can't be crawling under my truck and changing filters. Thats why I was wondering if there was a ball park mileage that you can head off the unexpected.

Nope. Any number you get from anyone is just going to be a wild a$$ guess.

Most of my users never even bother changing the filter until the next scheduled maintenance..

What year is his truck? Both 7.3 pre 99 and after are located on the top of the engine. I really doubt he has enouph gunk in his tank or fuel lines to flush at 100k. My 512,000 plus doesnt have any gunk in it and ive run every crappy variation of flamable garbage through it. In fact when I ran waste motor oil (very bad idea) the crap ended up in my filter. I went through bio just to clean everything back up. Now I run a 6 dollar pre pump filter and housing from napa. Housing was about 20-25 and the filters are 6 to 16 bucks. Do you have a TSC nearby? You can get pre pump filters all you need with cheap replacements.

I do believe it's a 7.3 and yes we have a TSC near by. Thanks I'll pass all this info along.

I didn't start running B20 in my 02 until I hit 155,000 and never saw any change in the filter. I checked it every 1500 miles the first 3 tanks and saw no signs of it getting dirty faster than normal. Hope this helps.

A lot depends on the quality of fuel he was previously running.
Like others have said buy an extra filter and put it under the seat or somwhere readily available.
Check the filter in use at each fillup.
Get ready to smile every time you pass your old fuel stop.

Do they run filters like the tractors, where they are clear. So you can visiably see the filter if its going bad or not?

You can go with a pre-pump filter like Kennedyford sugested or a cheaper one from NAPA like their 3001, it's clear so you can do a visual check.