I know the common wisdom is "it's never too early to start building your team" and getting professional advice. But in reality, as a self funded solo searcher, it's financially impractical for me to have a lawyer and accountant with me every step of the way. I've done a lot on my own -- I formed my LLC completely on my own, I drafted my PPM and 50% of the subscription/op agreements on my own, filed the state and SEC registrations on my own. So far, outside of mandatory filing/registration fees, I've spent <$1000 on legal/financial advice. 

However, I'm at a point now where I really need to start thinking about paying for professional services. But with a tight budget in mind, when exactly do you guys involve and start paying real money for lawyers/accountants?

Specifically, in the following timeline of a hypothetical search process, where and how in depth do you involve lawyers?
1) Searching / Prospecting
2) Connecting with potential targets and having broad convos
3) Sending an official IOI
4) Conducting prelim due diligence
5)Sending out a LOI
6) Conducting extensive due diligence
7)Submitting formal offer and closing