Not used it for a while?

Do not worry about it. I do understand how you are feeling, once started, we always want to finish it. There are times to let a book lie for a while, as you would lay down a fine wine, to lift it again from the cellar, blow the cobwebs and dust from it. It has only become sweeter and deeper for it's rest. I know, all to well, that such things are frustrating but sometimes a novel takes many years to write. Two years ago I lifted a dust encrusted bottle from the rack and loved the vintage, heady and deep, it had lain dormant for almost twenty years, filled with mystery and now with history, it was resurrected. The vine grew anew and wrapped all in it, the original and new melded together into a great (c)seller. Sorry, all, I could not resist the bad pun.

Often when a novel or piece of writing goes astray all that is needed is a break from it, a time to regather thought and focus, time to look at it with new eyes. I always save my work no matter how trivial as one day I may return to it and (hopefully) make it great.

It is true that If you do not finish a novel that you have started, it may grow mouldy, green and then turn to dust. Just as likely it gathers value, age and vintage and becomes better and better each time that you return to it.

It seems such a strange thing in today's world of instant gratification, where if I wish to listen to "Tom Waits" I call up videos on YouTube, ask "Alexa" to play his songs, the internet to provide his great lyrics but those very same songs took him a great deal of time to write and perfect. The same applies to books. Instant gratification is good but a book that has grown up, gained time and experience, the perseverance of the author the thought and rethinking many times over can be one of the greatest things in life.

People often forget that many of the greatest books written were produced by authors that wrote only one novel in their lifetime.

Not Used it in a while? Resurrect, rewrite, perfect and finish. Don't worry that it was from a few years ago, the occasional fellow has not pulled his/her writing skills in a while but they may have honed them in the meantime.