I'm not a wealthy man by any means. Hell, I'm living off VA disability... but even so, I could never stand to be moving a single sight from gun to gun for years on end, having to constantly re-zero every time... I just put one on every gun I want one on. I have one "good" red dot (Aimpoint) on my SHTF gun, but the rest are what I call "good enough" red dots. These are all Sig Romeo 5. These can normally be found for around $150. ($100 when I first started getting them) I have them on an AR pistol, and SBR, a .44 mag lever gun, a custom Lee Enfield No4 Mk1 "tanker", and my son's Mosin M44.
Consider what a sight allows you to do with your firearm. Put the bullet where it needs to go. (the entire reason for having it) Add to that the fact that nothing is faster than a red dot sight, and that it is an electronic device. It increases your effectiveness, but it has to be rugged enough to withstand any abuse it may get in the field. Taking bangs, getting dropped, bounced around in a vehicle, weather swings from mid summer to the depth of winter... A sight is the very LAST thing to save money on in a weapon system. It's where you splurge. Rather a good sight on a crap weapon, than the other way around. I'm not gonna say that the Sig Romeo 5 is top of the line, but I will say I wouldn't trust anything lessor, and I sure as hell wouldn't want to be needing a weapon, and have to swap over the sight at the last minute...
Consider investing on a sight for each...
Here is a video review on the Romeo 5. I didn't see it until after I got the first one, but it helped me decide to buy the rest....
The guy even blasts it with a shotgun... and it survives.