If you educate yourself about the legal requirements of your business, you will acquire a good grasp of when to use an online service like www.legalzoom.com or www.nolo.com, and when you should get your lawyer's help.
For example, if you want to organize a corporation or limited liability company for your single-owner business, your lawyer or accountant can advise you on which entity to choose, with the main considerations being income-tax driven, but you may choose to organize the entity yourself through legalzoom or nolo or another on-line service rather than paying a lawyer to do it. Compare prices and make your choice.
On the other hand, if you are organizing a business with one or more partners or investors, read up on the subject - but consult your lawyer and expect him or her to prepare at least the most imporant documents that create your company, such as the shareholders or members agreement or investor subscription agreement. The reason for relying on a lawyer is that legal training and business law experience is especially helpful in helping business partners to formulate their mutual expectations, create an effective division of labor, allocate risks and rewards appropriately among partners, prevent unnecessary conflicts among partners, and offer "pre-nup" suggestions for resolving conflicts that do arise and achieve an amicable divorce if necessary.
When in doubt, call your lawyer and ask if his or her input is needed. A good business lawyer will not run up an unreasonable bill advising on when not to use him or her, and won't shrink from advising you to do for yourself and what not to do without help.