I'd replace it if you think you are close to exceeding the capability of the psu by way of upgrading video card, or some other power hungry part. If you are just using the machine to check email and surf the web, you should probably be fine with what it came with.
Edit- After seeing the specs...
That is alot of laptops to fix in one day if you are fixing hardware problems. If you are dealing with software issues that can't exactly be blamed on Acer. Are you fixing screens or bad boards, keyboards, etc?