I have 2 questions

do any of you guys replace strings and reuse the previous ones used?
Im a college student and money having more than 4 bucks is rare.. and i want to take out the heavy strings im using now and place some lighter ones.. then perhaps switch back using the same strings? is this wise?

Next question.. any of you guys use vinci strings? they sell them for like 4-5 bucks at my campus store .. i just want to know what you guys think about them. I have a ultragp and wanted to know if this will give me some tone.. im already using the heavy strings and i already forgot what it use to sound like.
My uncle, who's been playing for like 30 years, says that Vinci strings are some of the best. I haven't personally tried them though so I don't know, but coming from him it probably means something.
I personally never ever reuse strings. You can hear tone changes when you have a transistion from the old string(s) to the new string(s), that ones more liable to break its usually more dirty, rough etc.

I love the sound of new strings so i just buy new packets of 6 strings even if its just the one string thats broke.

But i doubt theres any harm in keeping old strings and just replacing the odd one string at a time. I dont think it would do any hard to you or your guitar, just perhaps sound and feel different.

Best luck.
Been away, am back