# A single AI model or multi-LLM: which fits | Shimli > OpenAI went from 50% to 25% of enterprise usage in two years. Why depending on one model is a risk and how FusionAI picks the right one for each task. [Comparisons](https://www.shimliapp.com/en/comparar) AI models ## Marrying one AI model is betting that today's best will still be best tomorrow. The short answer The model market changes leaders in months: OpenAI went from 50% to 25% of enterprise usage between 2023 and 2025, according to Menlo Ventures, and models get retired with little notice. Building on a single provider means migrating every time. In Shimli, FusionAI picks the right model for each task and adopts better ones without you changing anything. 5 min read · Updated October 6, 2026 Why choosing well matters 50% → 25% is how far OpenAI's share of enterprise model usage fell between 2023 and mid-2025; Anthropic took the lead with 32% [Menlo Ventures · 2025 ↗](https://menlovc.com/2025-mid-year-llm-market-update/) 4.5 months is how long GPT-4.5 Preview lasted on OpenAI's API: launched in February 2025 and removed on July 14 [OpenAI, developer notice · 2025 ↗](https://community.openai.com/t/gpt-4-5-preview-model-will-be-removed-from-the-api-on-2025-07-14/1230050) The norm is to run several models in production; picking the right one for each use case is the main reason [a16z, CIO survey · 2025 ↗](https://a16z.com/ai-enterprise-2025/) ### What depending on a single provider costs No model is best at everything: one reasons better, another is faster, another costs less. And the ranking changes every few months. With a single model, your team - Uses the same model for everything, even if another is better at a task - Pays the large model's price even for simple tasks - Migrates against the clock when the model is retired - Retests the agent with every new version - Depends on a single provider's prices and terms Every provider change becomes a project. With FusionAI The agent has to read a receipt, decide on an extension and reply fast on WhatsApp. - FusionAI picks the right model for each task - We use the best models and evaluate them constantly - When a better one appears, it's adopted without you changing anything - Only stable, tested models run in production Three different tasks, the right model for each, without you choosing anything. ### The comparison, point by point It isn't about which model is best today, but what happens when it stops being so. | Criterion | A single model one provider | Multi-LLM with FusionAI automatic | | --- | --- | --- | | When a better model comes out | The code has to change and be retested | FusionAI evaluates and adopts it | | When the provider retires a model | Forced migration, on the provider's deadline | FusionAI moves the task to another model | | Different tasks | The same model for everything | The right model for each: reasoning, reading, replying fast | | Who picks the model | Your team, and it decides again with every change | FusionAI, automatically | | Provider dependency | Total: one provider's prices, limits and terms | None: the agent and its memory don't depend on the model | AI usage is paid in blocks of $49 per 2,450 queries, whichever model FusionAI uses. No accounts or contracts with model providers. [See pricing](https://www.shimliapp.com/en/precios) ### When each one fits It isn't a contest: they're tools for different problems. #### A single model may be enough if… - It's a prototype or a small internal use. - You have a team that can migrate when needed. #### Multi-LLM fits if… - The agent serves customers and can't stop for a provider change. - It does different tasks that are better solved by different models. - You don't want your operation to depend on one provider's prices. ### Frequently asked questions What people ask when comparing. Can I choose the model myself? – There's no need: FusionAI automatically picks the right model for each task. It's part of what keeps the agent independent of any provider. What happens to my agent when the model changes? + Nothing you need to do. The agent's instructions, rules and memory live in Shimli, not in the model, so the change doesn't affect how it works. Which models does Shimli use? + We use the best models on the market and evaluate them constantly. Our core orchestrator is FusionAI, and only stable, tested models run in production. Sources - Menlo Ventures, “2025 Mid-Year LLM Market Update” - OpenAI, “GPT-4.5-preview model will be removed from the API on 2025-07-14”, developer community - a16z, “How 100 Enterprise CIOs Are Building and Buying Gen AI in 2025” ### Create your first agent in under 10 minutes. Describe what you need to the assistant and watch the agent work. Or we book 30 minutes and look at it on your operation. [Create account](https://shimli.app/user/auth/create-account) Book a demo