Juniper Squamata Yellow Needles

[njt]

Hi,
I am a beginner and just starting with some bonsai plants at the moment. I am from Sydney Australia and have recently purchased a new bonsai 3 days ago. I have noticed some yellow needles on the underside of the plant (maybe because of lack of sunlight on the bottom). Is this normal? I have moved the plant indoors to take a clear photo. It normally sits in the sun for 6 hours during the day (early morning and middle of the day) and I was told by the nursery to water everyday. How often should it be watered, I have seen online to use a chopstick and only to water it when it is slightly moist. Thank you for any help

 

[ShimpakuBonsai]

Those are old needles and this looks normal to me, no worries.

 

[Shibui]

Needles on the underside are usually the oldest. Even in evergreen trees individual needles only have a finite lifespan - usually 2-3 years- Then they go brown and drop off. Meanwhile new needles have grown on the tips of shoots so there's always fresh, productive needles on conifers.
I guess that's the long way to say browning inner and lower needles is perfectly natural.

Allowing your juniper to grow without trimming will see the branches get longer and bare inner sections move further and further outward. To maintain compact shape and size long term you will need to trim and prune regularly.

Watering to schedule is bound to cause problems long term as plants use water more or less at different times of year and different conditions will also cause more or less evaporation. Water once a day through summer is probably OK but will keep the soil far too wet in winter and could cause root problems then. Once a day may not be enough for trees in smaller pots or with more open potting mix in summer. I water most of mine twice a day through most of summer.
Water as required is far better. The wood skewer or chopstick in the soil is a simple but effective soil moisture gauge and will allow you to water as needed.