I held onto my S4 for 4 years and upgraded to the Ultra1. It worked perfect besides the battery going under 80% by that time. I carried a power bank with me so I always had a charger. I now upgrade my watches 4-5 years now.I have an Apple Watch Series 4? Its looking rough and I think it might be time to upgrade. I wonder how long people tend to hold onto their watches. I could probably keep it until it no longer receives OS updates.