The short answer
Use the trial or return window to measure reliability in the rooms and at the times your household actually uses the connection.
Step by step
Keep the existing internet active and record its normal price, speed, latency, and reliability before starting the test.
Place the gateway in several supported locations, especially near windows, and let it stabilize after each move.
Test work calls, streaming, gaming, uploads, smart-home devices, VPN access, and peak-evening performance for several days.
Check data policies, equipment terms, regular price, discounts, return deadline, and whether service can be moved to another address.
Cancel the old service only after the new connection passes the complete household test and return periods are understood.
Before you finish
Keep screenshots, receipts, chat transcripts, confirmation numbers, and the first bill after a change. Carrier terms and account eligibility can change, so verify the final price and conditions directly before submitting an order.