Most builders will install either position, recognition, landing/taxi lights and or an anti collision strobe light on their airplane at some point during construction.
Some do not, and if you are flying day VFR only, I would recommend to install at least a red tail strobe or wingtip strobe lights as a bare minimum as can be required in some countries. To see and be seen is the credo, especially in circumstances where visibility is reduced and in high traffic situations around airports and in training areas, where instructors are busy with students.
Several manufacturers are selling LED position and landing lights (including LED strobes too), these are very reliable with a long service life, probably longer than the aircraft. Current draw is much less resulting in thinner cables and there is more weight savings too because the high voltage unit is no longer necessary.
On this page we show you were navigation and strobe lights should be installed to be legal.
Excerpt from the document:
All aircraft must have an approved anti-collision light and position light system for nighttime operations. The position lights consist of an Aviation Red on the left side, an Aviation Green on the right and an Aviation White taillight (REF. FAR 23.1389).
The anti-collision lighting system is required under FAR PART 91.205(c). There are different requirements affecting different aircraft. These aircraft are categorized by the date of application for type certificate. Home built aircraft are determined by the date of issuance of the Experimental Operating Limitations.
To continue reading see the pdf below: