In 2015, during Tanzania's General Election that pitted John Magufuli of Chama cha Mapinduzi against Chadema's Edward Lowassa, Kenyans had their -- mostly undeclared -- interests, just like Tanzanians in this year's Kenyan elections.
Dr Magufuli, who won the presidential election, is a longtime friend of Kenya's opposition chief Raila Odinga, who is running against President Uhuru Kenyatta for the second time.
In December 2012, when he was the Works minister, Dr Magufuli attended and addressed a campaign rally of Mr Odinga's Orange Democratic Movement party. This prompted Chadema to question the minister's move, which they said could potentially cause diplomatic tensions between Dar es Salaam and Nairobi.
CCM said Dr Magufuli had attended the event as Mr Odinga's friend.
When he ascended to power, some Kenyan media reported that the Kenyatta State House was uncomfortable with "Raila's man" at the helm.
But President Kenyatta embraced Dr Magufuli and the relations between the two governments have been cordial.
Mr Odinga's friendship with the Tanzanian leader has remained intact and personal. Mr Odinga and his wife Ida visited the Tanzanian first family in their home village in Chato District, in western Tanzania where they spent a week.
This year, as the campaigns in Kenya heated up, Jubilee politicians claimed that the opposition alliance Nasa, perhaps banking on its leader's relations with the Tanzanian president, had established a vote-tallying centre in Dar es Salaam's suburb of Kigamboni. Both Nasa and the Tanzanian government denied the claims.
While the Dar-Nairobi relations have been cordial, they have occasionally been rocky. A trade war between the two East African Community members has been simmering in recent weeks, in spite of the Common Market Protocol.
Officials of the two states met this week in Dar to iron out the differences, emanating from Kenya's ban of liquefied petroleum gas imports from Tanzania, on the heels of a ban by Tanzania on grain exports to Kenya. Dar also banned imports of tyres and milk products from Kenya.
After the two presidents intervened, the two nations opened up their border points.
Tanzania got the deal to build the pipeline from Hoima in Uganda to the port of Tanga. Nairobi had initially agreed on such a deal with Kampala.
Besides that, Nairobi has been on an unsuccessful charm offensive to convince Tanzania to sign the Economic Partnership Agreement between the EAC and the European Union, which would give Kenyan exporters duty-free entry into the EU market. Dar argues that it goes against its industrialisation plan, by allowing cheaper goods to compete with those from the local industries.
In Tuesday's polls, Tanzanian opposition party Chadema is supporting Jubilee's Kenyatta because, according to its chairman Freeman Mbowe, "Mr Kenyatta has demonstrated exemplary leadership."
Analysts say that even if Nasa were to win on Tuesday, Tanzania's interests will remain the same. Although some see Mr Odinga as softer towards Tanzania, the outstanding issues will not just go away.
Like the other neighbours, Tanzania is taking precautions in case the election results in violence like the one in 2007. Inspector General of Police Simon Sirro said he had put all the regions bordering Kenya on high alert to guard against possible illegal immigrants and rising crime levels.