First Check the Thithi. Every peoples 13th day they prepare their writing of Sivaloga prapthi date in English and Tamil or as left their panchang they follow in their language, and time of death. In this the Year, date, Paksham, Thithi at the time soul departing the body all are quoted. So as per this monthly quarterly and as per their custom dates are calculated. Then there are Act and Rules if certain thithi coincidence etc. If you look at the PANCHANGAM of next year you can probably locate it. Then your house Purohit will recheck it and confirm the dare. So also any monthly or quarterly is remaining they do it a day or two earlier so before the Varushamdheegam so we do our karma dutifully. Panchangam is very much essential and keep all the panchangam safely. Don't throw away any old Panchangam.
I tell you one incident in my life.
In the year 1985, there was an issue that our project machines were held up at Nepal Border, as the peoples who returns from our project do not hold documents. So me and my other engineer sent to release it and bring it back. The Engineer knew the English Date when the peoples returned some 3 or 4 years back.
When we contact our agent who used to do our customs work said it is not possible. I need our Hindu Calendar year, month and date.
We were returning to Hotel. Then I told my Engineer you be ready in the evening we go to temple as I saw the Krishna Swaminarayan temple on my way. He started getting angry. We have this problem but you are talking going to temple. I said just come with me. What are you going to do otherwise in the evening.
In the evening I took him to the temple. After Darshan I made him sit there. He was uneasy and to leave. I said just wait. At that time Pandit ji was coming from the temple pedestal. I got up greeted him with Namaskar. I requested him we need your help. He said tell me. I said we need Hindu date of a year which is Nepali year also. We had the English date and please let us know the Hindu Date. He took us to his room made us sit on a mat. He looked for the years Panchangam. Then he located English date and picked a paper and wrote the date in English and Date as per in Hindu Calendar year. We thanked him with Dakshina. My friend telling me I can't believe how your mind thinks and work. Next day the Engineer happily went to the agent and in 10 minutes he brought the release order and to make payment of custom duty. We left in the evening to our country by handing over the materials to transport to our office. So Hindu Calendar Panchangam is very much helpful.