I use it daily for business - probably 50 hours per week on average. It is working fine, but if given a choice I would rather replace proactively than reactively -- i.e. if it stops working I do not want to have downtime from work (I am self-employed). Thanks for your help!
Laptops aren't as easily repaired as desktops. A halfway talented guy can repair or replace nearly anything on a desktop (mostly replace), whereas that's harder to do on a laptop and often requires professional help--taking it to a shop.
And they are generally less durable due to heat issues and the design compromises made in the name of smaller size and less weight. They are inferior to PCs in all respects save one: portability.
I'd say you should drive it till it drops rather than proactively replace stuff that is working OK at the moment--you have no way of knowing whether the part you just replaced would have lasted another 5 minutes or another 5 years. Likewise, you can only speculate about the longevity of any new parts you put into it.
I might give you a different answer if you said you were a talented laptop repairman or that money is no object.
It's a fairly old laptop---the cost of doing any significant repair is likely to outweigh it's present market value.
I assume you could buy a replacement within a few hours or a few days at most if it drops dead.
If money is of little or no concern, you could always buy a cheap (possibly used) laptop or desktop and just put it in the closet for now. Break it out when the current machine fails if you just can't stand a few hours or few days of downtime.
You should certainly have any critical data on this laptop backed up in multiple ways since you use it in your business.
Any business should have a "disaster plan" of some type---which presumably would include a fall-back PC to the extent that is a critical item and downtime is unacceptable.
