RE: Upgrading from 2010 to 2018
HI Ghost87,
Do you have currently a VAR or Partner on file ? Is your maintenance contract current with Microsoft ? because the biggest problem right now is with many customers running on 'old' GP versions like 10, 2010 or 2013, is that they lapsed their maintenance contract, and thus are no longer eligible to upgrades on future versions (even 2015, 2016 or 2018/18.3), as they need licenses keys for each major GP version they want to upgrade..
I've see this many times, and their is no magic when your maintenance is expired.. You'll have to buy from scratch or opt for another solution (like hosted GP solutions, where you pay a monthly per-user fee).
If you're still under active contract, but don't want to use your regular partner, you can try to hire some independant consultants that might help you with that task. Based on the configuration of your environmnent and the number of ISV products that might be attached/linked to your GP, and the number of companies, this can take anyway between 50 to 150 hours to complete.
Hope this helps to build up a case for your company.
If you want to know more, send me a DM.