I started “collecting” tools a year ago and my first batteries are starting to go now. They’re actually still plenty good enough good enough for my impact driver (best tool ever) but they die too quickly in my chainsaw. Couldn’t say how many hours they’ve given me but it’s a lot.
- A Milwaukee right angle drill. I don't use it much, but when I need it, it's invaluable
- A Porter Cable circular saw. I get a bit more use out of this. Circular saws are so versatile.
- A hand-held power planer. I used this a lot fitting doors to irregular door jams. I've loaned it out quite a bit too. Like the right angle drill, I don't reach for it often now, but when I need it, I'm damn glad to have it.
- Just purchased a Makita track saw. I'm anticipating a lot of long rip cuts in the next few months. I could do this with a circular saw, but I really like the simplicity of the track saw.
- Power drill. I've had it forever. I rarely reach for it, but it's nice to know it's there.
For battery powered tools I have:
- Power drill. This is a must-have for battery. The convenience is worth having to get a new one every so often. I'm on my second one now. I started with a Craftsman a long time ago. I replaced the batteries once and now I can't get new ones.
- I'm considering a jig saw. I'm not sure. It feels like this would be more convenient w/o a cord, and they're cheap enough that I wouldn't worry about replacing it. Still undecided.
For yard tools, I can totally see going with battery powered as well. I'm considering an edger. I hate dealing with two-stroke engines, and a cord would be a huge PITA. I'll probably get a battery powered one and try to stay in the same brand for leaf blower and chainsaw.
[1] https://www.protoolreviews.com/news/power-tool-manufacturers...
The blower is fantastic and quiet at that too. Much more relaxing than a gas one making noise all the time. The edger is phenomenal but probably too much for my needs.
I've got too many corded tools, so my decision isn't generally choosing between cordless or corded, but rather deciding whether adding a cordless version will help me. My metric is that cordless tools are useful for short jobs where reducing the setup time helps (eg pick up a driver and use it). Corded tools take less maintenance and are adequate for jobs where you're already setting up a work area... which is most things involving a jigsaw. Not having to manage the cord during long cuts would be nice, but doesn't seem like it would make any task significantly easier. Then again if I didn't already have 2+ jigsaws I'd probably feel different.
power tools have changed dramatically in the last 20 years. what was good then is no good now due to greed. Makita has stayed someone consistent as they only have the same brand, same for Bosch, Hitachi and Metabo (although not going forward), but their individual product lines have drifted. eg Bosch jigsaws are still excellent, their circular saws are whatever, some makita impacts have a design flaw, etc.
But it's pretty much a given that anything like a cordless drill will have the batteries give out long before (and even multiple times) before you need to replace the tool itself. Batteries are consumables in any mis- to high-end product with a long lifetime, like it or not. (Same with cameras.)
Search for “battery repack”. The batteries inside are always a standard size, and can be replaced by cracking the case. There are specialist companies that do it, but you have to find them.
You can do it yourself if the tool is worth spending the time on - basic soldering skills, and glue the case back together after you break it open to replace the cells (ugly, but works).
A corded tool, I can leave in a box for 3 years, then pick up, plug in, and run it all day if I need to, then put it away for another few years, and never have to worry about it.
I think your idea of cost per month is good for things you use often. One thing I've been thinking about lately as I've undertaken a medium-sized kitchen renovation is the cost of ownership of tools. Since I'm not a professional I can't take a cost per month approach since I may not use the tool for many months at a time.
Instead I've been thinking about two things:
1. How many hours of operation can I get out of this tool? If I amortize those hours over my lifetime, will I ever have to buy the tool again? In this case a mid-range tool may be an A+ for me, but a B- for a professional.
2. What is the lifetime of a battery-powered version of the tool? I'm avoiding battery-powered tools (with a few exceptions, I'm looking at you power drill) because I'm concerned the batteries will fail before the tool does.
My ideal situation is that I buy these items once and never need to replace them. As an amateur, I should be able to do that without buying the most expensive tool. As a professional, I probably already have preferences and a strong opinion anyway.