Subaru electrical issue

I have a 95 Subaru Impreza. Often have to get a jump start, so replaced battery in October, but had to jump yesterday. I will get alternator checked tomorrow, but I suspect this has to do with the antitheft thingy. Could it be shorting or drawing power somehow?

Many things draw power constantly; the antitheft thingy, the radio, and the car’s computers, to name a few.

Is the antitheft thingy factory installed or aftermarket? If it were shorting it should blow a fuse.

Have the alternator tested. I wouldn’t be surprised if it’s time for a new one.

Thanks for this. I am not sure if the antitheft thingy (does it have a name?) is factory or not. I am the third owner, but once we rule out the alternator I will look further into that. Many thanks.