Wholesale speed tiers on the NBN can change even when your household devices and habits do not. When NBN Co enables higher maximum speeds on your technology type, retailers may launch new plans — but they are not obliged to move you automatically to the best value tier.
If you are on a 100/20-style plan, it is worth checking whether a 500/50 (or similar) offer exists at a modest price step-up that matches how you use the connection (4K streaming, large uploads, working from home).
Always confirm typical evening speeds published by the provider and any contract or modem terms before you switch.