To understand the difference, look at the roots. “Maintain” in Latin is a combination of “hand” + “hold”. “Sustain” is another Latin sourced word that means to hold up from below, bear, or endure.

Hello! "Sustain" is a verb that means to support, maintain, or endure over a period of time. It often refers to keeping something going or maintaining its condition or state. When I think of the word "sustain," I imagine a continuous and steady effort or action that keeps something alive, functioning, or lasting. When I hear the word "sustain," I might think of things like sustaining a note on a musical instrument, sustaining a business through difficult times, or sustaining a conversation by keeping it engaging and flowing. Now, let's talk about the differences between "sustain," "get," and "maintain": Sustain: As mentioned earlier, "sustain" implies keeping something going or maintaining its condition over time. It often involves providing the necessary resources, effort, or support to ensure that something continues or lasts. Get: "Get" is a more general verb that can mean to obtain, acquire, or receive something. It doesn't necessarily imply maintaining that thing over time; it's about acquiring it at a specific point in time. Maintain: "Maintain" means to keep something in a particular state, condition, or level. It involves preventing decline or deterioration and ensuring that something remains in the desired state. Unlike "sustain," which focuses on continuity, "maintain" emphasizes the consistent management of something's condition or state. In essence, "sustain" emphasizes keeping something ongoing or in existence, "get" refers to obtaining something, and "maintain" centers on preserving something's state or condition.

Sustain and maintain have very similar uses and are often interchangeable. I would say ‘sustain’ is often more abstract and less material, maintain is sometimes a more concrete set of tasks and errors. For example, sustaining a political movement, or sustaining focus; both take a will and effort to continue (be sustained; resilient) but isn’t well defined. Maintain is reminiscent of maintenance, you may ‘maintain’ a piece of machinery, oiling it, replacing parts, tuning. More concrete/specific. But, the distinction is soft, and you could say ‘maintain’ in most cases and it would sound natural, just maybe a slightly different subtext. For example, maintaining a political movement would make me think of organizing, fundraising, educating. Maintaining the struggle (sustaining actions) would be needed for a sustained (an achieved, continuous, state) movement.