Add Shut Off Valve for Bathroom Sink Lines

[RodNAtl]

Need some help. I've notice that my delta faucet is leaking and I am going to replace it but at the same time i thought I could also add shut off valves to the hot and cold water lines that running to the sink.

Has anyone done this before? Any concerns?
If so, is it pretty easy and are most valve sizes standard are what size valve would I need to get.

Any help would be great.

Thanks.
Rodney

[AlinCal]

Here is what I did for stops, pex x 3/8" comp. angle stops since my new faucet has 3/8 supply hoses on it factory (and most do come that way now).
So then for you I would do the same stops then use a supply hose to go to your delta(I am assuming it just has 1/2" supply connections in the valve body) Then if you ever upgrade your faucet you are ready to go.