I've bought bows mid-season, and dialed them in with a short practice session. Confidence comes with knowing YOUR abilities. The equipment can change and you can still be successful.
I start off at 20 yards and sling a few arrows. Check the results. Adjust the sites accordingly and repeat. After I'm dialed in at 20,and getting consistent groups, I'll step back to 30 yards and repeat the process.
If I'm using a multi-pin site, I'll leave the 20 yard pin in place and adjust the next one, till it's on at 30 yards. Repeat for the 40 yard pin.
Once I feel good with the accuracy, I swap out the feild points for my practice broadheads and repeat the whole process..20 yards, 30 yards, 40 yards, and make any small adjustments as I go.
Know your equipment. Be comfortable in your abilities.
Why did I change bows? One time was when my bow got ripped off.
And the other time was when my buddy left for a new job in Florida, and sold all his gear and I got a great deal on a better bow.