You should make the effort to have the best of everything for plenty of reasons - appearance and productivity.
But that doesn't mean people won't hire you with a 2002 truck and 5 year old equipment. It's a process.
I certainly don't think it ever makes sense to go out and buy a $50,000 truck and $40,000 worth of equipment if you cannot justify the expense and recover your investment.
When your truck, trailer, equipment and employees appear clean and well-kept, it does make an impression. People do take notice, just like they would if your rust-bucket pulled up with everything duct-taped, oil and black smoke spilling and pouring out all over the place.