At the outset of most projects, there typically exists a contracted scope of work, a defined contract value and a contract duration, or expected completion date. More often than not, projects encounter unforeseen or unanticipated issues that impact scope, cost and/or duration of the project. Increases to the contract amount and/or duration are typically the result of scope changes and/or delays to the progression of work. Any issue that impacts the contracted cost and/or time exposes the project owner to claims and/or requests by the contractor(s) for additional costs and/or extensions of time. Provided that a contract allows for a contractor to recover additional time and costs, proper and/or sufficient project records improve the contractor’s ability to substantiate and recover additional costs and/or time as well as the owner’s ability to defend against unjustified requests or claims by contractors. This paper focuses on the importance of a party’s typical practices of monitoring and documenting the costs and other data associated with changes and impacts to the work in order to maximize the party’s ability to sufficiently substantiate claims for additional time and/or costs, or defend against such claims. This paper also discusses the potential challenges that can occur when a party’s typical practices and contemporaneous records do not support a contractor’s claim or an owner’s defense.