The time frame for what exactly? If you built the new store on a Shopify development website and imported all your products and ran extensive tests, while you woocommerce store was still in operation, you could switch stores overnight and experience minimal downtime for your customers.
Hello you can find many many providers helping you to migrate to shopify, just search migrate to Shopify data migration find some top page, ask them any questions then to to their migration page, fill cart URL and API, then run. Your data including pictures will be transferred to Shopify totally automatically. It is very simple. You can do it with any platforms to Shopify. Goodluck!
WooCommerce and Demandware are two totally different beasts. If you're on woo, the chances of having a larger ecom tech stack is far less so is generally much, much easier. If you're coming form Demandware 3 months should be the baseline. I've seen shorter. I've seen longer.
It's super quick to set Shopify up as you've probably seen. Adding products and a gateway is speedy so you could be selling in a day. What takes the time is any data migration and middleware that may need to be customised or created. We also have no insights into your business needs and what training, support, changes, etc you need to give to various teams like Customer Service.
Sit down and work out all the dependencies and that should start to give some insights into the timeline.
Nick here from Shopify.
To follow up from what Jason said, it can be quick and easy to set up a Shopify store, but there are many factors to be considered it's hard to give an exact timeframe with just a monetary income. From the income figure you mentioned, it seems like the Plus plan would suit your needs and it could be worth reaching out to our plus sales team and giving them more details and they could give you a more direct timeframe and cost idea. You can reach out to the Plus team directly from here.
All the best, Nick