Low-current, momentary action pushbutton switches, such as PCB-mount ‘tactile’ types, are cheap, and available in an abundance of different styles. Latching types, on the other hand, are often larger, ...

[Patman2700] has a nice scope for his paintball gun that uses a red dot instead of cross-hairs. The problem is that he kept forgetting to turn it off which ended up running the batteries down ...