From my experience, it depends on the horse, their personality, training and energy level. Life happens to all of us, and there are times our horses "sit", so rest assured you are not alone.
If you are unsure of what she will be like once the weather breaks, I would suggest round work to assess her, until you are comfortable that she is going to be safe to get on.
I have one who is now 21, and for the last few years I leave him in NY for the winters, while I come home to va. He was unridden for as much as 6 months. Come spring-he is just like I rode him yesterday. I am careful though to make sure I gradually increase his work and stamina. My newer one, however, altho he would probably be fine, I would be more hesitant to do that with, so if he goes any time (like a week) without being ridden I do ground work first, then get one once I know he is listening.
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