When is a contract necessary?
"I want to make a few small structural and design changes to my home. Do I need to have a contract drafted for the work or can I get away with making small changes without using one?"

Answer from Ross:
As any of my clients know, I will always advocate for having a signed contract before starting work on any project. Not only do they ensure that both parties understand their respective roles and responsibilities but they also give you some protection if the project is not completed properly. With that said, there are specific contracts that should be used exclusively with designers, architects and contractors in addition to any contract you may need to execute with your bank or lending institution.
Luckily, as a client, your designer is responsible for giving you a contract to review and sign before entering into a work agreement. The form of this contract may be as simple as a proposal in letter form, or may be very formal (and complicated) like the AIA's owner-architect contract. Regardless of complexity, the following items should be addressed in your contract with a designer:
Names and contact info for both parties
Preferred mode of communication
Project address
Scope of proposed services with as many details as possible - often in this section, there will also be an approved rendering or sketch
Exclusions (items specifically NOT to be addressed)
Project schedule with milestones, especially for deliverables and owner-review periods
Project fees, including a detailed proposed budget and a notification system when you are approaching your budget limit
Indemnifications
Signature lines for both parties with dates
When it comes to a contract with a contractor, there are additional elements that need to be present:
Contractor licensing and bonding info
Project start and completion dates
Payment schedule
Incentives for meeting or outperforming schedules or budgets
Specific project notes such as: "Inform owner 3 days prior to disruption of utilities" or "Maintain a clean site, removing loose debris at the end of each work day" – be specific when it comes to this section as nothing is worse than going to turn on your shower and realizing that the water has been shutdown for the day
I recommend checking out some sample contracts for ideas of what to consider when constructing your own service agreement with your design professional. The AIA has a very good Residential and Small Commercial Project contract guide and the American Society of Interior Designers (ASID) has a great webinar on what to look for in a contract.
Remember, a good contract helps communicate expectations and benefits BOTH parties!