I have a set (of laser grips) on my 1911 and love them. For a person with trifocals, at times it is a necessity and other times just fun to use.
First of all, in bright light they don't show up well at all on a white/bright background. That is fine, when I am testing reloads or shooting for groups I take my time and can use my glasses to focus the iron sights. When I want to shoot in self defense mode, I shoot in dim light and use the laser to help develop a natural hold. What I really like is the ability to shoot accurately from any position. I don't need the sights, the pistol can be at my hip, chest level or turned in any direction.
For practicing developing a hold for different positions, they are perfect, you don't need to shoot at all. You can practice in your house without shooting a round. At times I will turn off all the lights and see just how I am doing.
My 1911 is rarely far from me. At night it is within reach and you don't have to turn on the laser. All it takes to activate it, is to naturally squeeze the grip and it goes on. It has an on/off switch that has been on for the last two years and will not affect the level of the battery at all. If it isn't used, there isn't a draw on the battery.
The first upgrade on a new 1911 for me would be the Crimson Trace.
Jim