When I was younger, I didn't use to have one and tried to cheapen out by reading contracts carefully without checking with a lawyer. One of those contracts was a rev share in exchange for free work I did (plus some work I paid other contractors to do), I didn't notice that there was an easy way to get out of the contract by the company. Once the company was successful thanks to the work I initially did, they used that to cut me out. If I had used a lawyer back then, I'd still be earning 150k a year from that contract...
So, yeah having a relationship with a lawyer in the same way you have a favorite dentist is worth it. Having the reflex of using a lawyer when possible potentially can save a lot of money down the road. And using a lawyer at first for less impactful work is sometimes a good way to find out if the lawyer is any good.
I'd actually suggest any consultant/contractor to have a lawyer, work with him to review every contract and budget a small percentage of your income on this every year.