Anthropic offers multiple Claude models and most business users don't know when model selection actually matters. For many tasks, Sonnet is indistinguishable from Opus and costs a fraction. For some tasks, Opus is worth every extra cent.
Claude Sonnet 4.5 is Anthropic's workhorse model. It is significantly faster than Opus - typical response latency is 2-4x lower - and cheaper via the API (approximately $3/$15 per million input/output tokens vs. $15/$75 for Opus). For a team running thousands of requests per month, this cost difference is substantial.
Claude Opus 4 is Anthropic's most capable model. It produces higher-quality output on complex tasks, maintains coherence better across very long outputs, and reasons more reliably on problems that require multiple logical steps. The tradeoff is speed and cost.
For Claude.ai subscribers on Teams plan, both models are available within the usage cap. You switch models per-conversation. The cost difference only becomes directly relevant at API pricing.
For these tasks, switching to Opus adds latency and cost without meaningfully improving output quality. Sonnet is the correct default.
The practical test: if you are frequently editing Sonnet's outputs heavily on a specific task type, try Opus. If the editing drops significantly, Opus is the right model for that workflow. If editing stays similar, Sonnet is sufficient.
Anthropic releases new model versions on a roughly 6-12 month cadence. The historical pattern: each new Sonnet version meaningfully closes the gap with the prior Opus version. By the time Opus 4 was released, Sonnet 4.5 outperformed Opus 3 on most benchmarks.
This means the right long-term posture is: configure your workflows and Projects to be model-agnostic where possible, default to the latest Sonnet, and upgrade selectively to Opus where the task justifies it. Don't lock yourself into specific model assumptions that will be outdated in 12 months.