Since a Schedule C allows for deduction of expenses, the removal of employee and other miscellaneous deductions under TCJA is not so much a consideration.
The biggest considerations are legal - liability isolation and the like. Again, con
The tax reasons are generally based on the TP's (Taxpayer's) whole situation, including other sources of income, family situation, immigration status, retirement plans/goals
C-Corps, Sub-S's and partnerships all require 'care and feeding'. Corporate paperwork, franchise tax and state/federal filings can easily consume $400-900, at a minimum. IRS forms 1120, 1120-S and 1065, and their state equivalents, may be extremely challenging and a very steep learning curve.
Some customers will not do business with a S/P; in those cases, creating an entity is the price of entry.
An entity might also be indicated when the TP wants to have an 'arms-length' contract with the entity, such as for an office rental or vehicle sale. In that case, the entity is used as a 'separate person'.
Summing up... If one is just starting out, I'd recommend keeping on a Schedule C (S/P), unless there are other considerations. If the legal advantages are needed, the D/E (see prior post) allows one to use an LLC for its entity purpose, but report it on a personal return.
And, yes, I'm doing this post for a mental break between completing last minute client returns.
Hope it helps,