Gemara

Bava Kama 75b: Testimony that cannot be Huzam is invalid when the witnesses do not know at what time they saw the testimony.

84b - Question: Judges of Chutz la'Aretz should be Sheluchim of judges in Eretz Yisrael to collect payments of double, four and five for theft!

Answer: They are Sheluchim to collect only principal, but not to collect fines.

Sanhedrin 2b - Question: The Mishnah teaches that monetary cases require three judges, and gives theft and wounds for examples. Why were admissions and loans omitted?

3a - Answer (Rava): Mid'Oraisa, three experts are needed also for admissions and loans. Mid'Rabanan, three laymen suffice for them due to Ne'ilas Delet (lest people be hesitant to lend out of fear that expert judges will not be available and thet will be unable to collect).

30b (Rav Yehudah): If the witnesses contradicted each other about Bedikos (matters not essential to the testimony), the testimony is valid for monetary cases.

32a (Mishnah #1): Drishah v'Chakirah applies to monetary and capital cases alike - "Mishpat Echad Yihyeh Lachem".

Contradiction (Mishnah #2): Postdated loan documents are Kesherim (even though Drishah v'Chakirah does not apply to them)!

Answer #1 (R. Chanina): Mid'Oraisa, Drishah v'Chakirah applies to monetary and capital cases alike. Chachamim enacted that monetary cases do not require Drishah v'Chakirah due to Ne'ilas Delet (lest potential lenders fear that the witnesses will not pass Drishah v'Chakirah).

Answer #2 (Rava): Mishnah #1 discusses fines. Ne'ilas Delet applies only to admissions and loans. Drishah v'Chakirah was abolished only for them.

Answer #3 (Rav Papa): Both discuss admissions and loans. Mishnah #1 discusses a Din Merumeh (Beis Din senses that the claim is false), Mishnah #2 is a normal case.

Rishonim

Rif and Rosh (Sanhedrin 10a and 4:1): Rav Papa answered that Drishah v'Chakirah is needed for monetary cases when it is a Din Merumeh.

Rambam (Hilchos Edus 1:5): Chakiros and Drishos are the primary testimony. Through them, one is liable or exempt. They specify the time and place, which are essential for Hazamah of witnesses.

Rambam (3:1): Drishah v'Chakirah applies to monetary and capital cases - "Mishpat Echad Yihyeh Lachem". Chachamim enacted that monetary cases do not require Drishah v'Chakirah due to Ne'ilas Delet. If the witnesses said 'he lent to him in front of us', even if they did not coordinate the month or place of the loan, their testimony is valid.

Rambam (2): This refers to loans, admissions, gifts, sales, etc. Fines require Drishah v'Chakirah, and also a Din Merumeh requires it.

Rambam (3): Even though monetary cases do not require Drishah v'Chakirah, if it was done and the witnesses contradicted each other, the testimony is Batel.

Rambam (Hilchos Malveh 17:9: If a document does not say where it was written, or it has no date, it is Kosher. In monetary cases we are not concerned for Drishah v'Chakirah, lest people be deterred from lending. Therefore, postdated documents are Kosher, even though Iy Efshar Lehazimah.

Rosh (Sanhedrin 1:1): Monetary cases do not require Drishah v'Chakirah, due to Ne'ilas Delet. Similarly, we do not require it or expert judges for Kesuvos, inheritance, and gifts. This is to thwart Resha'im, lest they commit fraud, confident that the victim will have difficulty finding experts and witnesses who can answer the Chakiros. The same applies to theft, for it is common. We require Drishah v'Chakirah and expert judges for injuries. The opinion (32a) that says that fines require Drishah v'Chakirah refers to everything that requires expert judges. The Gemara calls this 'fines.' In Bava Kama, we conclude that experts are needed for whatever is not common, i.e. injuries, but theft is common.

Rivash (266, cited in Beis Yosef 30 DH Aval Im): Monetary cases do not need Drishah v'Chakirah, due to Ne'ilas Delet. Divorce and Kidushin are like monetary cases; we learn from a Gezerah Shavah "Davar-Davar." If a case is Merumeh, we require Drishah v'Chakirah even for monetary cases. It seems that loans and admissions, even for a Din Merumeh, do not require the same Drishah v'Chakirah as for capital cases. We do not disqualify the testimony if he cannot answer one of the Chakiros. Even though the Mishnah equates Drishah v'Chakirah of monetary and capital cases, and Rav Papa says that it discusses a Din Merumeh, he means only that some Drishah v'Chakirah applies. The Ro'oh explained this way. It seems that the Ram mi'Kutzi agrees, for he says that a Din Merumeh requires Drishah v'Chakirah, and it is a Mitzvah to ask many questions.

Poskim

Shulchan Aruch (CM 30:1): Witnesses for monetary cases except for inhuries do not require Drishah v'Chakirah. Even if they did not coordinate the month or place of the loan, their testimony is valid. If it appears to the judge that it is a Din Merumeh, it requires Drishah v'Chakirah to reach the proper verdict.

Beis Yosef (DH Ein): The three answers do not argue with each other. The Rosh holds that only injuries are like fines. Tosfos equates theft to injuries (it requires Drishah v'Chakirah). It is not clear how the Rambam holds.

SMA (1): The Tur and Mechaber said that inhuries require Drishah v'Chakirah. The same applies to everything mentioned in Siman 1 (which is uncommon or entails normally monetary loss).

SMA (2): 'They did not coordinate the month or place' is whether Ploni claims two loans and each witness testifies about one loan (at different times), or he claims one loan and one of the witnesses did not know the time. The Mechaber discusses the latter case.

Gra (1 and 1:19): The Shulchan Aruch rules like the Rosh, who says that in Bava Kama we conclude that we judge theft in Chutz la'Aretz because it is common. If so, the Sugyos in Sanhedrin (2b) and Gitin (88b) are unlike the Halachah! This is difficult.

Shach (1): Even if the judge wants to be stringent, he should not do Drishah v'Chakirah.

Shulchan Aruch (2): Even though we do not require Drishah v'Chakirah for monetary cases, if the witnesses contradicted each other in Drishos v'Chakiros, their testimony is Batel.

Shach (5,16): It is Batel because it is Iy Efshar Lehazimah. This is unlike the Rivash (above, who is Machshir witnesses who cannot answer Chakiros). Bava Kama 75b says that such testimony is worthless! It is difficult to say that this refers only to fines. Also the Mordechai and Nimukei Yosef require Efshar Lehazimah. They merely say that presumably, the witnesses know the time and place, so we need not check if they know. Indeed, if we find that they do not know, the testimony is invalid.

Nesivos ha'Mishpat (Chidushim 16): Darchei Moshe brings many who do not require Efshar Lehazimah for monetary cases. All agree that if the witnesses could not answer Chakiros, it is Kosher. They need not testify in a way that enables Hazamah. The argument is about a case in which even if they testified in a way that enables Hazamah (they answered the Chakiros), Hazamah would be impossible, e.g. they are related to the judges. This is like the Urim v'Tumim (Urim 1), unlike the Shach.