DPF question. New to trucking.

Not really. Not knowing what they are doing is the main issue. Always better to learn on somebody else's dime, using them as a resource to answer questions and lend a helping hand when needed to help you succeed (because when you succeed, they profit). The larger the company, the bigger the support network, from knowing what shops do good work for reasonable rates to the shops that'll bend you over, keep the truck for a month, and STILL not fix it...to discounts on things like fuel, tires, etc...and even help with things like billing (leased on, you get paid whether they collect or not), IFTA filings, etc.

When you're on your own, who do you call when you have a problem?

Until you've been out here long enough to get a feel for who you can trust and where to go for certain things, it's an uphill battle. Hell, even with years of experience and a rolodex full of contacts, it's STILL an uphill battle, albeit not quite as steep. The point some folks are trying to make is that this isn't an easy business. Thinking it will be for you...that you're somehow different...will cause you to miss important details you migh otherwise see, because you're overly confident that you've got this in the bag. If you don't know what you're doing, your bag is empty.