I'm blessed that I am retired and fish 4-5 days a week. I don't go out in the kayak in the winter though unless it is a really nice day. I was in the missile, radar business for 38 years and the best way to stay up on a particular system was repeated use....checks...adjustment of that system. It is the same with using an si unit. The more time you can get on it the more you will retain the understanding and ease of use of it. I have the time and for that I am thankful. I have a nephew who can only get his boat out a couple of times a year and he only has a 2d unit with GPS but has long since forgot how to use it.

Regards