After looking at my two little painting efforts, I can now say I do feel confident about taking up oil painting again. Not that those two were particularly good, (they weren't,) but I'm convinced that I still retain much of what I learned previously and can get back "up to speed" relatively soon.
The point where I left off was not a bad place, I'd gotten comfortable with moving the paint around, getting to do what I wanted it to, and was beginning to seek out and develop a sense of "personal style." But when you do get away from painting for an extended period, your skills do diminish. At least I find that is true of me.
Right now, I'm fairly happy with my drawing skills, but I see I definitely need to get control of my values. That is to say, the relative lightness and darkness of tones that give depth and shape to things that exist in three dimensions, but are being rendered on a two dimensional surface. If you get the value right, the hue (or color) can be off, but the painting will still be believable. But even with perfect color matching, when the values are wrong, the entire painting is wrong.
My next couple of paintings will be primarily exercises aimed towards understanding the values and getting them right. When I get a few done, I'll post them here and explain what I'm learning from them.
Spring Hill, FL