IMHO.... No

Must i clear old layer of wax before i apply new one?

Read online suggested period for 1 wax is every 2 months

So after 2 months, i must clear old wax (not sure how to get this done) before i apply new wax?

i used to be fancy about those rain repellent thingy
now i just clay and clean my windscreen with alcohol/APC once a while and top up with spray wax .. tada same thing

Hi there everyone, I'll be picking up my car this week.  It's a second hand City (used 1 year +).  Can anyone recommend some good car wash/wax/polish workshop? Planning to send it in for a one time fix.

Read a lot of bad reviews on Cars International.

Thanks a lot! =)

My car is only 5 months old and I already can feel roughness on the paint.

Never thought I need to clay my car so soon. 

I think it really depends on what is your results after compounding. If after compounding your car shine is back with no holograms or swirls, then it is probably okay to wax after that. If u are a generally careful car washer, then actually u may not need to compound also, just polish and wax will do just fine as u remove less clear coat that way.

More importantly, please clay before compounding/polishing. There is alot of stubborn dirt that wont get removed from just washing alone, so claying is a very important preparation step before compounding/polishing.

The stubborn dirt can appear due to many reasons, especially if dirty water dry on your bonnet and the heat from the engine and sun bakes the dirt into the paint. Rather than compounding/polishing such stains off, I believe claying or wax cleaner should also do just fine.

Great sharing session! Pleasure to meet u bro!
May I ask how u currently do your compounding? By hand or rotary?

From my experience, wax durability is up to the wax itself. I always prefer to apply 2 thin coats of wax compared to 1 thick coat, because the excess from thick coat just dries up and gets wiped off, so doesnt help to protect the car and is wasted.

Yes, generally always try the least aggressive method first, which in this case can be wax cleaner. If wax cleaner cant remove then move on to polish, if polish cant remove move on to compound, if compound cant remove move on to wet sanding.

Wow lucky I choose osren claybar over 3M...Osren claybar cost RM40 but can break into 3-4 pieces so is more than enough for 1 car.

There are many fake 3M clay bars online. Just be careful. PG clay bars are quite decent for the price and could be easily found in Parkson, Aeon, Tesco.

My personal 2 sen is water beading capabilities helps to reduce the amount of rain stuck on the car when it is moving. Its like how when u apply RainX on your windshield, then drive over 50-80kmh and no need use wiper because wind speed pushes the water off.

Water sheeting is important for stationary cars in rainy season to reduce the amount of water stuck on car.

Both water beading and/or water sheeting is good for drying car convenience after washing.

I dont place a very high importance on gloss effect because the bigger and more common issue affecting gloss to me is haze and swirls, which only can be solved with polishing. So I prefer to side on durability of the protection.

Again, just my 2 sen.

clay is better at removing those contaminants that are sticking up on the paint, i do not believe sealant behave like that else it will feel rough after you wax or seal the paint, therefore, clay is not effective at removing sealant esp the finer grade. Use polish to remove if you dont want guesswork. Or reapply the wax again on that spot, the solvent of the new wax will remove the old one if you are lucky

pure sealant/wax alone does not natively provide UV protection so some manufacturers will add in those addictive to give it that feature but most of them did not advertise about it. So, 
the only 'mainstream' wax that dares to advertise UV protection is OCW, optimum car wax. Its UV protection is patented, you can actually google the patent no. and study it. Lots of technical info inside. It is convincing enough to me that OCW is my go to wax if you are focusing on UV protection instead. FYI, most of the UV protection come from the car clear coat itself which has finite service life 

Why do you need to polish a new car?