It depends on your staff and how significant the switch is. Change is hard. When Sandlot Sports went from handwritten triplicate order forms to using a business management software, it was a massive undertaking company-wide.
Every aspect of the order process changed, and we spent a lot of time prepping staff before we even purchased the software. We worked hard to get the team on board. If you get your staff to buy in, it makes the whole process easier.
I think a six-month period should be a reasonable expectation. In six months, there should be enough “tricks” or ‘hiccups” that pop up for you to learn from and move on. You won’t master your software in six months, but with proper training, you’ll have a great base of knowledge. If it’s a priority, you and your staff will implement it much quicker.