No hard and fast rule. All depends on how much funds you can spare at that moment. I’d rather take maximum finance and invest the said amount elsewhere.
Do not wash them, water will start collecting inside. Just replace the headlamps. Sets for the i10 are freely available in local markets and cost about 1000bucks apiece.
yes ! right !…but they can be opened and washed if somehow dust entered.(be sure with the bulb holder)……but if they are old..better is to replace them..i got swift onces for 890