According to the regulations of Vietnamese airlines, each traveler can carry up to 30 kg of checked baggage and 7kg of hand luggage. Each kg of excess carry will be taxed by Vietnam Airlines at $10 / kg (in Vietnam) and $6 / kg (in Russia).
According to Aeroflot regulations, each traveler can only bring up to 23 kg of luggage (at the time of promotion can carry 2 pieces of baggage with a weight of no more than 23 kg each) and deposit and 10 kg of hand luggage.
Aeroflot stated that the baggage must have a total size of 3 sides not exceeding 158 cm, with hand luggage: no more than 55 cm long, not more than 40 cm wide, not more than 25 cm high.
Domestic flights in Russia checked baggage usually apply 20 kg / 1 person. Note: there are a number of low-cost aviation required to pay extra for checked baggage and very limited hand baggage in both volume and capacity (eg: Pobeda, Azimut...).
Foreign tourists are allowed to buy duty-free goods worth US $300 or less, if a goods over US $300 is required to pay import taxes themselves in accordance with Vietnamese Customs (Note: Vietnam Customs will fix goods according to the value of Vietnamese goods).
You absolutely do not bring live food, vegetables, fish sauce, shrimp sauce ... in luggage for food safety reasons.
In hand luggage, do not bring sharp objects such as knives, glue, nail clippers ... and cream or liquid products such as drinking water, perfume, shampoo, shower gel, skin cream ...
All valuables such as gold, diamonds, notebooks, and cameras require you to bring people, not to your checked baggage (laptop and camera will not count on luggage your laptop).