I wash my car once a month normally.During rains I need to do it more frequently. I have seen it in one of the youtube videos where the person was of the view washing your vehicle too often is bad. I want to know is it correct? Driving your vehicle with with road side mud stuck to under car's body ok? How often should i wash my car? And what are general tips for maintaining a car/bike during rains.
Washing your car once a month is acceptable. It is not too much. What is more important is the technique and materials used (nonabrasive soap and sponge, drying towel, and wax). There are plenty of sites with tips on proper car care to cover this.
Washing your car is a good thing because, not only does it keep it looking nice, it helps prevent corrosion as well. Removing dirt and other filth prevents damage to the paint's surface.
Bird poop, tree sap, and other material that lands on your car can harm the paint if left. Heat and the sun intensify the effect. So, washing is preventative maintenance.
From what I have read, there seems to be a "rule of thumb" to wash your car every two weeks, depending on your environment. Those who live in dirtier environments more, others who garage their car and drive it little will obviously need to wash it less.
I'll chime in with a totally different angle: Once or twice a year is fine unless it's getting covered in something nasty like tree sap or excessive bird poop.
More important is washing stuff off the underside (where you can't see, and most corrosion starts) and fixing paint chips and other damage - again, underneath is more prone and very few people ever go there.
My reason? I live in a country where the roads are salted in winter, and I drive 4x4's off-road, so cleaning all the abrasive & corrosive / moisture-retaining mud off the mechanicals & chassis is far higher importance to the health of the vehicle than the smooth sealed and resilient paint job on the top, which these days shrugs off almost anything unless it's damaged.
Chassis / subframes, driveshafts, ball joints, and other moving parts, sills, nooks and crannies that trap dirt & moisture, drain/vent holes that get blocked are all usually not touched by people who wash the shiny side only as they're hidden from view.
Also, there's better things to do with your life than polish your car every Sunday. Go out and drive it, for example...
I just pay the small amount it costs for an automated car wash, saves me time and effort and does as good a job on the "shiny side" as I could.
Edit to add: As our roads are saltier than our fish & chips at the first sign of a mild chill, I wash my daily driver more often during winter to keep the salt minimally crusty, but only the cheapest automated wash that includes the under-body wash. I'm doing 100 miles/day so it builds up quick.
Also, any time I'm doing maintenance under the vehicle I get busy with a can of Dinitrol underbody wax on anything within reach before I pack the tools away, it seals stuff up, stops corrosion and sheds water & crud. You don't have to be very tidy with it underneath, just squirt it around as cheap insurance.