In my case, I brought in the QoE provider once I secured financing, and even though I had selected my counsel, I didn't fully engage them until I completed the underwriting process for the loan.

Adding one piece nobody mentioned: for trades and industrials, the highest-value pre-LOI diligence often isn't financial. It's operational and structural. License qualifier transfer, surety/bonding re-underwriting, key employee retention plans, customer relationship transferability, union or bargaining unit change-of-control provisions. None of these are typical QoE scope and none are typical legal DD scope. They live in their own bucket. For my own search (commercial trades focus), I'm doing this work myself pre-LOI because my background lets me. Buyers without that background should consider engaging an operational advisor with industry experience in parallel with QoE, not after it. The financial DD can confirm earnings are real, but if the license can't transfer or the surety won't re-underwrite under new ownership, the earnings don't matter.